question stringlengths 3 301 | answer stringlengths 9 26.1k | context list |
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why does the connection strength between a phone and a wifi router fluxuate, even when neither are being touched? | Your connection strength isn't just determined by the strength of the signal between you and your phone, it is also impacted by the noise in the environment
While the signal strength may remain constant, if the noise increases because of a leaky microwave or increased WiFi traffic from your neighbor's router then the signal to noise ratio drops and you router may need to send messages slower to ensure that they get through to your phone | [
"A mobile handset which is moving in a cell will record a signal strength that varies. Signal strength is subject to slow fading, fast fading and interference from other signals, resulting in degradation of the carrier-to-interference ratio (C/I). A high C/I ratio yields quality communication. A good C/I ratio is a... |
Would taking a cellulase supplement the way lactose intolerant people take lactase allow a human to each grass and other no digestible plant matter? If so, could this be a way of addressing world hunger? | Potentially. It's questionable whether it could provide complete nutrition on its own though, there are limited studies of use of cellulase in the diet of farm animals which so far have only been mildly exploratory.
However, world hunger in the modern age is rarely a problem of production but rather of distribution (typically due to the lack of rule of law in an area, or due to intentionally created starvation). If you had the means to ship a bottle of cellulase supplements to a starving population then you would also have the capability to ship them rice, so it's rather a moot point whether or not it would be possible. | [
"Lactase is an enzyme that breaks down the disaccharide lactose to its component parts, glucose and galactose. Glucose and galactose can be absorbed by the small intestine. Approximately 65 percent of the adult population produce only small amounts of lactase and are unable to eat unfermented milk-based foods. This... |
how does a smart phone responds to a touch? | The inside of the screen carries a small charge. Placing an object, like a finger, on the outside that can act as the second half of a capacitor and distorts the charge pattern. The position of the distortion can be traced by the circuitry to know what action to hairdressing on its location
Think about those toys with the plasma inside where the arc follows your finger as you move it on the outside of the glass globe.
EDIT - Damn you autocorrect and touchscreen tablet! I'll leave it there for the giggles. Should have been " action to take depending on its location" or something like that. | [
"Handheld technologies use a panel that carries an electrical charge. When a finger touches the screen, the touch disrupts the panel's electrical field. The disruption is registered as a computer event (gesture) and may be sent to the software, which may then initiates a response to the gesture event.\n",
"A prox... |
the relation between inflation, bill denomination and printing money. | All money only exists as a matter of 'trust' by us, of it's ability to buy a 'thing' we want. It is the intermediary between two barters. It has no intrinsic value whatsoever. All money is 'printed' or 'created' out of fresh air by a statutory source (central bank or whomever) and leaked out into the economy by loaning it to other banks, who loan it out to you, your employers and other financial institutions. Inflation is the thing that occurs when our bartering is inequitable. This is when Mr. X sells his car to Mrs. Y, for more than it's actual worth.... Mr.X makes a 'profit' from Mrs.Y, who is in turn less well off than she should be if the deal was 'fair' Mr.X will use this extra potential to lessen the value of all other money, by now using it on other items he would not have been able to afford if he had made a 'fair trade'. This goes on all the time, millions of times over and the value of each unit of money is thus devalued. The Nation is not 'worth' less though, so the creators of the barter intermediary component, money, need to put more of the stuff back into the system to 'top it back up' to reflect the estimated 'worth' of Everything . OK, maybe a bit over simplistic, but it pretty much explains it. In the Old Days, when things were simpler and Gold was the Standard which determined the value of everything, because of it's rarity and almost constant quantity, money remained worth it's original value far longer ! | [
"Conceptually, inflation refers to the general trend of prices, not changes in any specific price. For example, if people choose to buy more cucumbers than tomatoes, cucumbers consequently become more expensive and tomatoes cheaper. These changes are not related to inflation; they reflect a shift in tastes. Inflati... |
can a planet without conditions similar to earth support any life at all, or have we just not found organisms that require other conditions? | It's the latter. We only know life on earth -- life as we know it. It's possible there could be exotic forms of life elsewhere, but we have no idea what it would look like or how to find it. So we focus on the life we understand, because that's what we're best at finding.
To some degree though, we know the chemicals our life is based on are probably some of the best for "life". Carbon has specific properties that make it very nice for replication and other life functions. Silicon is very similar to carbon, which is why you often hear about people looking for "silicon based life" -- it's the most likely other element that could produce organisms that follow similar mechanics as ours. | [
"Due to the harsh conditions on the surface, little of the planet has been explored; in addition to the fact that life as currently understood may not necessarily be the same in other parts of the universe, the extent of the tenacity of life on Earth itself has not yet been shown. Creatures known as extremophiles e... |
How were the economic structures during the classical era in the mediterranean cities? | The Roman Empire doesn't seem to have had a formal legal control of business in the same way Medieval cities did with guilds. The question of market fairs is a bit more complex. We know they existed, and were probably controlled through local town governing authorities, but it is difficult to know how this impacted business outside of market days. The undeniable existence of permanent streetfront shops argues against an idea of mercantile activity being overly restricted outside of those days.
The closest thing to a guild structure you will find are the *collegia*. I'll paste in a discussion I gave of them a few days ago:
> The most well known labor organization of sorts in the Roman world was the collegium, which became prominent and important seemingly everywhere across the empire, although the specific modes of organization seem to have differed. For example, merchants in the East seem to have primarily organized themselves along communal lines (religious, ethnic, familial etc) while evidence from Lyon seems to point towards merchants organizing themselves along specific goods carried. This, of course, is not easily applicable to other professions, but it shows some of the diversity.
> Anyway, collegia seem to have begun as religious and burial organizations, but they quickly acquired commercial and social characters. This is all rather difficult to untangle and requires using a lot of varied evidence. I'll just give three, to give an idea: In Egypt, the environmental conditions allow for the survival of documentary papyrus and so we know an awful lot about collegia there, and we see a great deal of market organization and negotiation in the documents. In Asia Minor, literary evidence allows us to see examples of certain workmen organizations opposing the activity of the imperial elite (specifically the orator Dio Chrysostom) and prevailing, their collective economic interests defeating a very well connected person's political interests. In Pompeii, we see graffiti showing the prominent social role of collegia, and we even have wall paintings of something like festival floats. The problem with integrating is that these are fundamentally different types of evidence—we have no grafitti and wall paintings in Egypt, no papyri in Asia Minor, no literary descriptions for Pompeii. So are the role of collegia the same everywhere, but we just have different sets of evidence? Or are they actually very different?
The *collegia* do not seem to have had the same sort of legal control over business as guilds did, but they may have wielded extensive social control, and they could directly control the activities of its members. For example, we have papyri from Egypt that describe how a particular *collegium* sold the right to engage in certain types of economic activity to one of its members, and the punishment for those who attempted to engage in that economic activity in competition with the person who bought the contract. | [
"By the thirteenth and fourteenth centuries some cities become powerful states, taking surrounding areas under their control or establishing extensive maritime empires. In Italy medieval communes developed into city-states including the Republic of Venice and the Republic of Genoa. These cities, with populations in... |
how come the train tracks don't blow up when it rains? | > Why hasn't a fuse blown/breaker tripped like it does when I throw my toaster in the bath.
Actually this does happen from time to time. It's pretty rare thanks to good engineering and the fact that most train systems have been around long enough for weak spots that are likely to cause this to have been identified and fixed.
The breakers in your house are designed with home living in mind, not with trains. The breakers that a train system would use will tolerate a huge amount of current flow before they trip. When it rains, some current does get grounded, but it's usually not enough for the electrical system to be affected. Remember, the third rail can throw off enough current to kill a person without the breakers ever tripping.
All that said, the breakers on a train system will likely also be much fancier that the ones in your home. There are breakers that can monitor for current leak that is not a train and lower the voltage to lessen the loss of current without opening the circuit. If there is a train going by, then it will bring the voltage back up and just tolerate the loss of current until the train is gone. Some systems can shut off entire sections of track if there won't be a train coming by anytime soon.
If this seems a bit wasteful to you... you are right it is. But there is a point of diminishing returns for fixing such a minor problem. | [
"The rain concerned railway officials, who feared that landslides could hit the hillside line serving the city. Local officers organized a patrol to check conditions of the railway, and drove a service vehicle along part of the track, returning minutes before the disaster.\n",
"Though rail tracks were held in pla... |
Why is it so hard to program an effective anti cheat system in online games? | > My question now is, why it is apperently not possible for the game to detect that this kind of information is displayed when it shouldnt.
Simply put, because the "hack" is usually a separate piece of software running on its own, that is telling the game that it is allowed. At least for FPS games in general, hacks usually insert themselves between the "mod" part of the game, and the "engine" part; the engine does all the communication with the server and changing/rendering whatever it is told to, it does all the heavy lifting. The "mod" controls what the rules of the game are, and determines what to tell the engine to do. If you tell the engine to spawn a player at some point, it will do it; but the mod determines whether this is allowed or not. Most FPS hacks work by "faking" both the mod and engine parts, so that the mod thinks it's communicating with the engine, and vice versa, but in reality both of them are communicating with the hack, and the hack is able to tell the engine to do things that the mod wouldn't normally tell it to do -- such as making walls invisible, rendering players off-screen, or in an RTS, something like revealing fog of war or spawning units for free.
In general, programs are not able to detect or modify what other programs are doing unless they are designed for it. They can be designed to detect and modify a program's behaviour in a specific way (the way a hack targets a specific game's code; note that hacks are specific to each game, and the same hacks won't work for different games), or they can do so in a general way (the way anti-virus software scans code to detect malicious code patterns). It is always much eaiser to do it for specific software than for general software -- this is why making hacks is much easier than detecting them, and also why anti-virus scanners have databases of viruses; so they can catch many specific viruses that are already known. This is in addition to the "heuristic" scan which attempts to detect unknown viruses.
An anti-cheat program would need to work similarly to an anti-virus program -- it would need to be able to detect known cheats through a specific way of detecting them (this requires being familiar with various cheat software), and also it would need to be able to detect unknown cheats in a general way, which is usually very difficult if not impossible. Also, whenever an anti-cheat program comes out with a way to detect a specific hack, usually the hack developer will release a new version of the hack that can't be detected the same way, so it ends up being a back-and-forth race; the honest gamer/developer can never win.
So the question is, how does one detect whether hacks are active, in general? It's very difficult and it depends on the game and on the specific hack. Many hacks also are designed specifically to hide themselves from the more common detection methods, making the task even more difficult.
> Why can't the game not detect that this kind of information should not be displayed when there is no unit or spell to reveal the fog of war in this area?
Because the "mod" part of the game isn't actually in control of the engine anymore -- the hack has inserted itself between the mod and the engine, and is able to change the interaction between them, so that the engine thinks it's okay to do things that the mod wouldn't do. The mod has to *trust* that what the engine tells it is correct (for example, if the engine comes back and says "player X moved to location B," the mod has to accept this information from the engine or else there may not be data synchronization between the server and the players. Some mods are designed to detect certain engine changes that shouldn't be allowed, and can take measures to preserve the game's integrity -- usually this results in one or all players being "dropped" or otherwise disconnected. Sometimes it also manifests as sudden lag or as packet loss. This is especially common in RTS games.
> Couldnt you just programm a code that logs what has been displayed at what time to the player and what units where near this area so he could have had vision of it and then when an area is displayed by the client but there was no mean of units nearby it prooves the maphacking.
Yes, you can easily prove that someone is cheating by observing the behaviour of their game. But this is something that a human can do, not a computer. Just because you can log what the engine (or mod) is doing, doesn't mean that you can easily detect that what it's doing is wrong. And good anti-cheat software often will be able to detect these things, by doing exactly this. To give an example, anti-cheat software for the FPS game Counter-Strike often *also* inserts itself between the mod and the engine, and then scrutinizes the engine to look for prohibited or unusual changes.
Also, this type of thinking doesn't work for all hacks. For example, consider an FPS game "aimbot" that automatically aims at people's heads. Since mouse input is a human-controlled thing, and humans can give all kinds of input (fast, jerky, erratic input, or slow, smooth input, etc.) it's usually not possible to verify whether a human or a bot is in control of the input. You might be able to detect very "shaky" movement, but a good bot would be programmed to have less shaking and more smoothness, so as to avoid detection that way. This is also true for things like "turbo buttons" or "button macros" on a console game or emulator.
Hope that helps! | [
"There are many facets of cheating in online games which make the creation of a system to stop cheating very difficult; however, game developers and third party software developers have created or are developing technologies that attempt to prevent cheating. Such countermeasures are commonly used in video games, wi... |
why cant heat/any kind of energy be used to create matter when matter can create heat | Theoretically it could be, although from the equation E=mc^2 where E is energy, m is mass and c is the speed of light, you can see that for each small amount of mass you create needs an astronomically huge amount of energy to create it. At the moment this is just totally impractical to do.
To get 1kg of mass, you would need to 90,000,000,000,000,000 joules of energy. When you consider that just 1 joule is the energy required to lift a small apple one meter in the air, then you can see how much that is.
You would need enough energy to lift 90,000 *trillion* apples or 189,653,355 Titanics (the ship) by one meter. | [
"Historically, confusion about mass being \"converted\" to energy has been aided by confusion between mass and \"matter\", where matter is defined as fermion particles. In such a definition, electromagnetic radiation and kinetic energy (or heat) are not considered \"matter\". In some situations, matter may indeed b... |
why do doctors move the stethoscope around, rather than just place it on your heart? | Each area that they place the stethoscope allows them to listen to the 4 different valves in your heart. If a murmur (abnormal sound) is heard at a specific area, it can tell the doctor which valve or part of the heart may be affected. | [
"Stethoscopes roughly match the acoustical impedance of the human body, so they transmit sounds from a patient's chest to the doctor's ear much more effectively than the air does. Putting an ear to someone's chest would have a similar effect.\n",
"A doctor will listen to the heart with stethoscope. A \"tumor plop... |
In the US during WWII, how did rationing work on the homefront if people went to a restaurant? Did people have to give the ration coupons/cards to the restaurant in addition to payment? | The restaurants had to collect points in order to buy more stock for their kitchens. They took the points to the local ration board and exchanged them for vouchers that allowed them to buy quantities of food at a time.
Lots more here: _URL_0_ | [
"By the end of 1942, ration coupons were used for nine other items. Typewriters, gasoline, bicycles, footwear, silk, nylon, fuel oil, stoves, meat, lard, shortening and food oils, cheese, butter, margarine, processed foods (canned, bottled, and frozen), dried fruits, canned milk, firewood and coal, jams, jellies, a... |
cell cycle and mitosis? | The cell grows and grows through the G1 phase. When it gets big enough, it enters the S phase, where the DNA replicates. Then it goes to the M phase, mitosis. This is where it splits. The two daughter cells repeat this process. | [
"In cell biology, mitosis () is a part of the cell cycle when replicated chromosomes are separated into two new nuclei. Cell division gives rise to genetically identical cells in which the number of chromosomes is maintained. In general, mitosis (division of the nucleus) is preceded by the S stage of interphase (du... |
the impossible trinity of economics | Free movement of capital allows you to participate in the international economy, particularly the financial aspects of international trade. Restricting it will isolate your economy, reducing its potential growth by restricting the ability to work with investors and companies outside your country.
You also asked about the current US exchange rate. It is not stable, and fluctuates constantly on the international currency market. | [
"The idea of the impossible trinity went from theoretical curiosity to becoming the foundation of open economy macroeconomics in the 1980s, by which time capital controls had broken down in many countries, and conflicts were visible between pegged exchange rates and monetary policy autonomy. While one version of th... |
What is thought to have stabilized earths magnetic field? | I'm a graduate student in earth science, but I'm studying glaciology, not geomagnetism. Nonetheless, I'll give this a go:
The Earth's magnetic field is caused by convection cells in the liquid iron/nickel outer core. It is not known (at least by me) what causes reversals, but my understanding is that they are a chaotic process.
The "fixation" you are referring to was not permanent. The "Cretaceous Long Normal" was a period when the magnetic field had a stable direction for several tens of millions of years. However, after that it went back to irregular oscillations, as it did before. The last reversal was the Brunhes-Matuyama reversal, about 800,000 years ago.
Also, note that Earth's magnetic poles are never truly fixed. Even in between reversals they wander on short timescales (decades to centuries). This drift has been measured and documented within the past few hundred years. | [
"Over the life of the Earth, the orientation of Earth's magnetic field has reversed many times, with geomagnetic north becoming geomagnetic south and vice versa – an event known as a geomagnetic reversal. Evidence of geomagnetic reversals can be seen at mid-ocean ridges where tectonic plates move apart. As magma se... |
Is anything really impossible? | If you can define your initial and final states precisely in quantum mechanical terms, and if you know exactly what quantum theory you're adopting, a probability for going from initial to final state could exist.
As you say, the probabilities of all sorts of silly things happening will be extremely tiny but not zero.
What those stupidly tiny probabilities are will depend on exactly what theory you're adopting. It's best to bear in mind that distinguishing between quantum theories at that level of detail is not feasible, so it's not really a question that can be answered scientifically.
If absolutely conserved quantities exist in your theory, then probabilities *will* be strictly zero if your initial and final states have different values for those quantities.
As an example, in a theory that absolutely conserves charge locally, the probability of even one electron disappearing or appearing is exactly zero. Almost every sane quantum theory adopts the absolute charge conservation locally, so that puts a restriction on what can or can't happen in that kind of a theory. | [
"Statistically \"impossible\" events are often called miracles. For instance, when three classmates accidentally meet in a different country decades after having left school, they may consider this as \"miraculous\". However, a colossal number of events happen every moment on earth; thus extremely unlikely coincide... |
After the Second World War, why did Germany abandon the development of the Panzerkampfwagen VI line of tanks and instead develop the Leopard tanks? | The original Tiger tank had a very large amount of problems, the greatest of which was that Allied medium tanks had equivalent firepower in 1944, just over a year after the Tiger first saw combat, but at half the weight. The Germans realized this, and the Tiger B/Tiger II/King Tiger, the development of which began before the first Tiger left the factory, had very little in common with the original Tiger tank. However, even the new Tiger tank was vulnerable to the gun of the Soviet IS-2 and American Pershing at its inception, in addition to lighter guns (17 pdr and D-10) mounted on medium tanks and medium tank destroyers, which again caused the Germans to seek a replacement design. The heavy Maus and E-100 tanks that would be impervious (at least frontally) to these guns ended up being cancelled because they were simply impractical. The decreasing quality of German armour meant that armour had to grow thicker and thicker in order to resist Allied weapons, making these superheavy tanks incredibly impractical, even compared to the Tigers.
By the time the German army was allowed to rebuild after the war, the heavy tank concept has taken enormous steps forward. The Soviets built the IS-7, a heavy tank with the size and weight of the King Tiger and enough armour protection to be impervious to the 128 mm gun of the Jagdtiger and Maus. That wasn't all, the new generation of heavy tanks, the Object 752 and Object 777 had as much effective armour as the E-100 while weighing a third as much. The Tigers, already not exactly progressive designs in the 1940s, looked hilariously primitive by comparison.
Sources:
*Interrogation of Herr Stiele Von Heydekampf: German Tank & Engine Program*
*Ministry of Supply Armour Branch Report on Armour Quality & Vulnerability of Royal Tiger*
*Otchet po ispytnaniyu snaryadnym obstrelom lobovykh detaley korpusa i bashni nemetskogo tyazhelogo tanka Tigr B*
Yuri Pasholok, *Panzerkampfwagen Maus*
Yuri Pasholok, *Neschastlivye Tri Semyorki*
Nikolai Nevsky, *IS-7 Titan Opozdavshiy na Voynu*
| [
"After the war, the Germans were given US equipment and the Panzerlehrbataillon armour forces established in April 1956. The Leopard tank project started in November 1956 in order to develop a modern German tank, the \"Standard-Panzer\", to replace the Bundeswehr's United States-built M47 and M48 Patton tanks, whic... |
how can ants jump with these small legs? | O. rixosus as the only ant species that can jump with either its legs or its mandibles. Trap-jaw ants are known for using their powerful jaws to launch themselves into the air, somersaulting several times their own body length to evade predators. | [
"The female worker ants do not have wings and reproductive females lose their wings after their mating flights in order to begin their colonies. Therefore, unlike their wasp ancestors, most ants travel by walking. Some species are capable of leaping. For example, Jerdon's jumping ant (\"Harpegnathos saltator\") is ... |
why do mobile game ads look nothing like the actual game play? | Because it works and false advertising is a vague law that is hard to enforce outside of the U.S.
Just getting people to download your game makes it appear higher on lists that gets more people to download your game, they don't care if you uninstall it right after, their hope is you will download it, put in a bit of effort and enjoy it, if not, you will make them appear on higher lists which might help them in the long run. | [
"One form of in-game mobile advertising is what allows players to actually play. As a new and effective form of advertising, it allows consumers to try out the content before they actually install it. This type of marketing can also really attract the attention of users like casual players. These advertising blur t... |
tessellation (video games) | [NVidia has some good sample images](_URL_0_)
Tessellation basically takes a shape/set of vertices and smooths them by creating more "in between" vertices that try to counteract sharp edges. This can be done dynamically so objects use more polygons the closer they get to the camera (so distant objects aren't as straining on the hardware). It's an automatic process so it's limited by how well it's implemented and by the original model. | [
"3D Tetris is a puzzle video game developed by Technology and Entertainment Software and published by Nintendo. It was initially released for the Virtual Boy on March 22, 1996, in North America only. The game allows players to control multiple falling blocks, rotating and positioning them to clear layers in a \"Wel... |
What is the geologist/hydrologist opinion on Fraking to extract shale gas? | Professional hydrogeologist, here. I have ZERO actual experience with fracking, but I know some things about well construction and the failure thereof. I also know about contaminant transport in groundwater, though unconsolidated sediments are my usual playground (as opposed to the actual-rock that shale is).
It appears to me from my cursory reading on the subject that the problems occurring related to fracking are not caused by the fracturing of the rock, but due to poor construction of the wells. A poorly-constructed well becomes a conduit from down deep (where the natural gas and fracking additives are) to shallower depths (where municipal and residential wells will typically be located). The additives and natural gas run up the side of the well casing and contaminate shallower aquifers.
In my lightly-informed opinion, the fracking industry is shooting themselves in the foot by not self-imposing robust well-construction standards that properly seal off the wellbore. A guy who can light his tap water on fire won't care much whether that occurred due to deep fracturing 2000 feet down, or due to a failed seal in the injection well near his household well.
So, it seems to me that it is largely an engineering problem that has been allowed to become a political problem. | [
"Mining oil shale involves a number of environmental impacts, more pronounced in surface mining than in underground mining. These include acid drainage induced by the sudden rapid exposure and subsequent oxidation of formerly buried materials, the introduction of metals including mercury into surface-water and grou... |
Was there still any undiscovered land left by the time the aviation age came about? | [There were islands discovered with satelite imagery](_URL_0_), but I don't think that's really what you meant. You're more talking about significant land masses.
I think the most important would be Antarctica. The Coastlines had (generally) been mapped in piecemeal efforts, but [significant exploration of the inland area was done in modern times](_URL_1_). | [
"Virtually none of the old airport area exists as it did prior to European settlement. Only the foundations of the Eagle Farm Settlement survive, having been covered with fill in 1942. The Allison Engine Testing Stands and Second World War Hangar No. 7 from World War II also survived on the former airport site and ... |
Theoretically, how high must a building/structure be in order for it to be seen from all points on given hemisphere. | 45-deg away from an object on the earth (radius 6378.1 km) an object would have to be 2642 km high to be seen above the horizon.
Your line of sight being tangent to the curvature, you form a right triangle between you, the top of the building, and the center of the earth. The hypotenuse of the triangle is the distance from the center of the earth to the top of the building.
You would never be able to see a building 90-deg around the earth. You line of sight would be parallel to the building. | [
"List of buildings under construction which are higher than 90 m, including spires and architectural details. Based on floorcounts and floorheights; buildings without official height (including spires and architectural details) are also included as they are estimated to be higher than 90 m.\n",
"BULLET::::- Scale... |
How does electromagnetic interaction work? | Despite not having mass, photons do carry momentum, so the simplistic view of the photon "bouncing" off of the charge and transferring some momentum to it is not necessarily a bad way to picture it conceptually.
Edit: Just so we're clear, I'm not saying this is the correct picture, but if you're trying to grasp how a photon can be a force carrier conceptually, this is the way I would think about it initially (until you get introduced to quantum field theory!).
If you're wondering where the energy comes from, it turns out there is energy stored in electromagnetic fields. The way this is usually introduced is to think about the work (read: energy) you need to put into a system in order to bring two like charges together.
| [
"The electromagnetic force is responsible for practically all phenomena one encounters in daily life above the nuclear scale, with the exception of gravity. Roughly speaking, all the forces involved in interactions between atoms can be explained by the electromagnetic force acting between the electrically charged a... |
why do classical musicians and singers use sheet music / words whereas any other type of musician / singers learns the music / words. | Refer to this:
_URL_0_
You will also note that in comparison with "other types" of music, classical compositions tend to be more complex and long to be un-intuitive or difficult to memorize and retain reliably. | [
"Classical musicians playing orchestral works, chamber music, sonatas and singing choral works ordinarily have the sheet music in front of them on a music stand when performing (or held in front of them in a music folder, in the case of a choir), with the exception of solo instrumental performances of solo pieces, ... |
why do some subreddits have 20+ mods, even though some of them don't do anything? | Some may mod quietly, and never really comment, while others are more known because they constantly comment
Some may have stopped using Reddit, but no one's removed them from the mod list yet
Some may have been made a mod, just because of who the are/who they're friends with
Some may only deal with a certain aspect of the subreddit, like designing the layout, and don't actively participate in the moderating of it
There's dozens of reason why someone could be a mod of a sub without looking like they're doing anything. | [
"Mods (short for modifications) are an optional upgrade for characters within the game. Once the player's account reaches level 50, Mods become available to any of their characters that are level 50 or above. There are different categories of mods, each of which yields a different primary effect on the stats of the... |
How is online gaming possible if there must be some delay? | Modern games tend to employ two different techniques simultaneously in order to compensate for lag, but players with lower latency will still have a small advantage.
1. **Server state rewind**: You're playing an FPS at home and you pull the trigger. At that moment, the stuff you see on your screen is already out of date by 20-50ms. And the command to fire your gun doesn't reach the server for *another* 20-50ms. But the server knows *when* you fired the gun, so it just rewinds the game to that exact moment to find out what you hit.
2. **Client-side prediction**: Certain actions that you perform in the game (firing, moving, jumping, whatever) don't actually execute until the server receives the command. But the game would feel terribly sluggish if your client were to wait for official confirmation. So your client *simulates* the command locally under the assumption that the server will allow the action. You pull the trigger, and your client immediately plays a gunshot sound and draws tracer rounds on the screen. You *feel* like it executed immediately... but other players in the game actually don't see your shot until 100ms later.
These techniques allow games to feel responsive and accurate, but they can still cause conflicts. Sometimes you pull the trigger, but you're already dead on the server (somebody shot you and you don't know it yet) so the action isn't actually performed. You feel like the game robbed you of a kill because that's what it looked like on your screen. | [
"There are various methods for reducing or disguising delays, though many of these have their drawbacks and may not be applicable in all cases. If synchronization is not possible by the game itself, the clients may be able to choose to play on servers in geographical proximity to themselves in order to reduce laten... |
how do i begin to invest my money in penny stocks? | Penny stocks are anything but a sure bet, especially if you're trying to day trade and therefore eating brokerage fees against your small amount of principal. If you need a small amount of steady income, you're much better off working your ass off to find a job, living off whatever money you planned to put into penny stocks. | [
"When it comes to financing a purchase of stocks there are two ways: purchasing stock with money that is currently in the buyer's ownership, or by buying stock on margin. Buying stock on margin means buying stock with money borrowed against the value of stocks in the same account. These stocks, or collateral, guara... |
why do men's jean sizes have inseam and waist dimensions while women's jeans just have numbers (i.e. 4, 5, 6 vs. 32x34)? | Some people are going to hate me for this answer, but at some level many women don't like objective measures of reality and store vendors don't want it. A man for the most part regards the circumference of his waist as a statement of fact even if he isn't particularly pleased with the number. For whatever reason women take this stuff a lot more personally, so instead of a real measurement some phony number is used.
The problem is that nobody really knows what those numbers mean, so you get a size 4 that is quite different from one vendor to another. It doesn't take long to see that some clothing vendor will make a larger version of a size 4 to flatter someone and make the sale.
I'm baffled by it, but that is the closest explanation I can come up with for it. I know some women who find the whole matter insulting, as they should. An entire industry thinks that women can't choose clothing based on objective measurements. | [
"The waist is typically smaller than the bust and hips, unless there is a high proportion of body fat distributed around it. How much the bust or hips inflect inward, towards the waist, determines a woman's structural shape. The hourglass shape is present in only about 8% of women.\n",
"BULLET::::- Hourglass shap... |
If quarks are supposed to come in quark-antiquark pairs, how is it there are only 3 quarks, and no antiquarks, in protons and neutrons? | Quarks don't have to exist in pairs of quarks and antiquarks. Any QCD bound state must have zero net color charge. There are many ways that you can combine quarks and antiquarks such that their color charges sum to zero.
The main possibilities are a quark and an antiquark (mesons), three quarks (baryons), or three antiquarks (antibaryons). Then there are other, more exotic exotic possibilities, like four quarks and one antiquark (pentaquarks), etc. | [
"The quarks are bound together by the strong force, which acts in such a way as to cancel the colour charges within the particle. In a meson, this means a quark is partnered with an antiquark with an opposite colour charge – blue and antiblue, for example – while in a baryon, the three quarks have between them all ... |
How does light reflect in every direction if it is a single particle? | For large systems like light bouncing off the moon, it is important to keep in mind that there are an unimaginably large number of light particles (called photons) bouncing off the moon.
Each one is going in only one direction, but because there are so many, there are always going to be a lot that are going right towards your eye, allowing you to see them.
The answer to your other question is a bit more subtle. If only one photon bounces off an object, then it can only be detected at one location, to there is no multiplication going on, but before it is detected, it does indeed spread out, and can interfere with itself or other photons over a large volume.
For more on that, try looking up Young's double slit experiment. | [
"To see how, note that we can measure the position of a particle by bouncing light off it – but measuring the position accurately requires light of short wavelength. Light with a short wavelength consists of photons of high energy. If the energy of these photons exceeds , when one hits the particle whose position i... |
what would happen if a blob of water is introduced into vaccum without gravity? | It would boil, whether there is gravity or not, in a vacuum. You could get a spherical shape if you had it in a pressurized environment e.g. on the ISS. This is also not "without gravity" but often what people think of when they say a zero grav environment, since it is in free fall (you and the water could float). | [
"Aside from storage, the main role of the central vacuole is to maintain turgor pressure against the cell wall. Proteins found in the tonoplast (aquaporins) control the flow of water into and out of the vacuole through active transport, pumping potassium (K) ions into and out of the vacuolar interior. Due to osmosi... |
if they have cameras/sensors that clearly show if a baseball is a strike/foul/ball or even if a runner is safe/out on base, why does baseball still use umpires? | Some neutral party needs to make the judgment call, so an umpire is necessary to some extent. Video can assist with this, however, games would take too long if every call was made with reference to video. It's simply easier and faster to have umpires make most of the calls.
Many sports do make use of video for refereeing, but have compromised between total accuracy and speed. For example, in field hockey, each team is allotted a maximum number of times that they may appeal an umpire's decision and request a review of the video. This limits frivolous use and keeps the game going. | [
"Despite the warning track's presence, it is common to see outfielders crash into the wall to make a catch, due to a desire to field the play regardless of the outcome and/or because they fail to register the warning in time (as the track is on the ground, an outfielder pursuing a fly ball in the air will be lookin... |
Why is the tongue the fastest healing organ in the body? | is the tongue the fastest healing organ? I always thought it was the cornea... | [
"Because of the tongue's exceptional healing ability, piercings can close very fast. Even completely healed holes can close up in a matter of hours, and larger-stretched holes can close in just a few days. The length of time for the hole to heal varies greatly from person to person – some people with larger-stretch... |
sellers listing items for dramatically under retail on amazon | Not everyone bothers to ask for their $3.50 back.
... it was about that time I realized that the Amazon seller was about 8 stories tall and a crustacean from the protozoic era. | [
"Pricesearcher is an independent e-commerce search engine launched in the UK in 2016 which helps shoppers find the best prices for products online. It does not use the traditional Price Comparison Website (PCW) model adopted by comparison sites such as Moneysupermarket.com and search engines such as Google Shopping... |
Is it pure coincidence that the rotation rates of Mars and Earth are both 24 hours (-4 & +39 min)? | It's just a coincidence, with a large enough set of known planets you could say if it was an uncommon speed. But as you point out, their days are only roughly 24 hours, it's your choice of unit and rounding that creates the illusion if a pattern. | [
"The sidereal rotational period of Mars—its rotation compared to the fixed stars—is only 24 hours, 37 minutes and 22.66 seconds. The solar day lasts slightly longer because of its orbit around the sun which requires it to turn slightly further on its axis.\n",
"Only about 50° of the martian phase curve can be obs... |
What factors led to cultures in Mesopotamia to transition from nomadic to sedentary living? | Before the advent of agriculture most human movements can be roughly explained in terms of climate and resources. The story of our transition from nomadic to sedentary life is no exception, and in fact begins around the end of the last ice age.
The cold and dry climate of the Pleistocene Ice Age made resources relatively scarce. With more of the world’s water locked away in glaciers, the river systems that later supported agriculture were not yet the abundant, fertile places we know them to be. Without the pre existing knowledge of agriculture, there simply wasn’t a place bountiful enough in animal and plant life for nomads to settle long-term. They could basically stay in a place until it’s resources were exhausted or their food moved.
By 11,000 the climate was far more conducive to the proliferation of flora and fauna, especially near the equator. The Natufians of the Levant began to experiment with more permanent settlements. I say experiment because they were still a hunter-gatherer society, but the greater availability of resources allowed them to forage and hunt from central, stationary communities. However, for about 1,000 years beginning in 10,800 Earth temporarily endured a cold swing with cold climates reminiscent of the Pleistocene Ice Age. Global glaciation brought on droughts and the Nartufians, who may have been using wild cereals to make bread as early as 12,000, could no longer depend on an abundance of wild crops and animals to sustain them. To defray the loss of natural resources, they began collecting seeds and clearing out scrub land to plant them in.
This question is hotly debated within the scientific community and the above is answer is somewhat controversial depending on how you define sedentary living. It’s not entirely accurate to say that the Nartufians were the first domestic farmers, as simply planting and harvesting does not qualify as “agriculture” in the sense that we think of it in Mesopotamia or the Nile Valley. However, they took an important step towards developing a sustainable model for sedentary living.
To put it more concisely, sedentary communities largely resulted from human response to local climate change. Sedentary life became sustainable when these communities began to experiment with plant domestication, and ultimately became the norm when animal domestication and technological advances gave way to large scale agriculture | [
"The notion of living a nomadic lifestyle in mobile collectives and following the seasons is older than civilization itself. Such examples of early tribes like Native Americans wandered across the nation, periodically moving location to maximise the advantages to climate and the environment. Throughout old Europe, ... |
when i choose the "skip" option on certain files in a torrent, why do some of them sometimes still download, often even 100% of the file? | The content of a torrent is split into blocks of a fixed size. That's the smallest unit your client can reliably download. Each block can contain one or more files (or parts of them).
When you choose to skip a file, but the block containing this file also contains another file that you didn't choose to skip, the whole block has to be downloaded regardless.
Many groups intentionally use this effect to make it impossible to skip their annoying "downloaded_from_foo!.nfo" files by making that the first file in the torrent. | [
"Due to the nature of this approach, the download of any file can be halted at any time and be resumed at a later date, without the loss of previously downloaded information, which in turn makes BitTorrent particularly useful in the transfer of larger files. This also enables the client to seek out readily availabl... |
Did the American entry into the First World War have a significant impact on the eventual outcome? | Yes, absolutely - though not in the way you might think!
The US came into the war just as Russia was knocked out of it and the Germany high command realised that with the massive manpower and manufacturing base of the US, it was only a matter of time before the war was lost. It was therefore imperative to try and win the war before the Americans arrived en masse - there would be over 300,000 US soldiers in France by May 1918 and a further million by August.
Forces were redeployed from Russia as fast as they could and a massive offensive - Operation Michael - was launched in March 1918. The German spring offensive broke through the British lines on the Somme and succeeded (finally!) in breaking the trench deadlock and getting through into open country, thanks to tactics learned on the eastern front - a short "hurricane bombardment" instead of days of shelling, and infiltration and stormtrooper tactics.
With the British forces reeling back and the French fighting on the flanks, it looked for a while as if the Germans might actually manage to take Paris, and Haig issued a general order that all British forces were to stand firm, backs to the wall.
Unfortunately for the Germans, the offensive petered out short of Paris thanks to a combination of dogged British defence and French attacks along the flanks of the German line; the difficulties the Germans found in advancing over the shell-ravaged Somme battlefields from two years earlier and the tendency of German troops to drop everything and start looting whenever they took a British supply dump.
Once the German offensive ground to a halt in August, the Allies counter-attacked, pushing the Germans back to the old trench line and then beyond it, in the "Hundred Days Offensive" which continued until the Armistice in 1918. These last 9 months of war were a far cry from the trench warfare that is the usual image of WWI and actually it wasn't until the Hundred Days that US forces were engaged in any number, so the American experiences of WWI were in general somewhat different from those of the British and French, with Pershing's American Expeditionary Force deployed along the Ardennes region in the French sector and attacking along the Verdun-Sedan axis.
So in WWI the American troops played a significant part in winning the war without actually doing a huge amount of the fighting. If the war had gone on another six months or so in the trench warfare phase, we'd have seen huge American armies manning the trenches and probably having their own Sommes and Verduns while they learned the lessons of Trench Warfare, but as it was it was the mere threat of the American arrival that forced the Germans to risk it all on an all-or-nothing attack.
| [
"The war marked American entry into world affairs. Since then, the U.S. has had a significant hand in various conflicts around the world, and entered many treaties and agreements. The Panic of 1893 was over by this point, and the U.S. entered a long and prosperous period of economic and population growth, and techn... |
Are slavs native to Balkans, and if not, who dominated The Balkans before they went there? | The Slavs as a linguistic group didn't arrive in the Balkans until the migration period of the 6th century. Around the same time, the region was also invaded by the Turkic Bulgars, who were gradually Slavicised until all that was left was the name. As to who dominated the Balkans before, the answer is Rome, who ruled the region from around 20 CE until the arrival of the Slavs and Bulgars. The Adriatic coast had been a Roman province for much longer than that, and Emperor Diocletian's palace forms the center of the Croatian city of Split. Before that, the eastern portions, which are now Macedonia and Bulgaria, where ruled by the Persians for a time and subsequently the Greeks.
However, the answer to who the dominant population was in the Balkans is very different. In the east, the main groups where the Thracians and the Dacians, who had frequent contact with the Greeks to the south, but spoke a very different language and tended to no organize politically on a large scale. The western Balkans were inhabited by the Illyrians, of who not much is actually known. We know that they were never united as one "Illyrian" cultural group, and that the place known as Illyria by the Greeks and Romans was inhabited by numerous tribes who didn't necessarily have a lot in common. Some of them where influenced by Celtic cultures from northern Italy and modern day Austria. Occasionally, one group would rise to become particularly powerful, but no one dominated the whole region politically. | [
"The Early Slavs raided the Western Balkans, including Bosnia, in the 6th and early 7th century (amid the Migration Period), and were composed of small tribal units drawn from a single Slavic confederation known to the Byzantines as the \"Sclaveni\" (whilst the related \"Antes\", roughly speaking, colonized the eas... |
How viable is Replacement cloning? | There isn't a lot of promise at all, in fact there is very little research into this at all, our best technology can't even reconnect nerves currently, otherwise all those paraplegics caused by spinal injuries would be able to be "fixed".
I don't know what you have been reading, but it isn't current scientific research.
| [
"Cloning is the method discussed as an option for bringing back extinct species, by extracting the nucleus from a preserved cell from the extinct species and swapping it into an egg of the nearest living relative. This egg can then be inserted into a relative host. It is important to note that this method can only ... |
rogaine, and why i can't use it to grow a beard. | Im actually wondering this myself... | [
"Bort is an English name meaning \"fortified.\" It is also an eastern Ashkenazic surname that refers to a man with a remarkable beard. It originates from the Yiddish word \"bord\" and the German \"Bart,\" which both mean \"beard.\" It may also originate from the Polish word \"borta,\" a loanword from the German \"b... |
A rather short question: How did Australia become a thing? | Well, that's a big question, but the various answers about Australia [in our FAQ on Oceania](_URL_3_) are definitely a good place for you to start, and some answers within that that are directly relevant to your questions include:
* my answer to [Why was Australia colonized? What motivated people to travel so far only to settle in such a dangerous place?](_URL_1_)
* an answer by /u/Algernon_Asimov on [
What would life have been like back in the colonization days for a prisoner shipped from England to Australia once he/she stepped off the boat?](_URL_2_), and
* /u/AbandoningAll's answer to [Were indigenous Australians ever enslaved?](_URL_0_) | [
"The history of Australia from 1901–1945 begins with the federation of the six colonies to create the Commonwealth of Australia. The young nation joined Britain in the First World War, suffered through the Great Depression in Australia as part of the global Great Depression and again joined Britain in the Second Wo... |
why do parts of a product cost more to repair than the whole thing? | Say it's a 20c resistor, but the company has a call-out fee, an hourly charge, overcharge you for parts, etc. It might come out higher due to the labour costs where you are compared to costs of shipping + a whole new TV - especially if it's a cheap TV. Another option is that it's older and parts are harder to find (which seems unlikely for a TV, but will often happen with cars) | [
"Repairable components tend to be more expensive than non-repairable components (consumables). This is because for items that are inexpensive to procure, it is often more cost-effective not to maintain (repair) them. Repair costs can be expensive, including costs for the labor for the removal the broken or worn out... |
Why do cows have four stomachs and what does each stomach do? | 4 digestive departments of a cow's stomach region:
1. The Rumen – this is the largest part and holds upto 50 gallons of partially digested food. This is where the ‘cud’ comes from. Good bacteria in the Rumen helps soften and digest the cows food and provides protein for the cow.
2. The Recticulum – this part of the stomach is called the ‘hardware’ stomach. This is because if the cow eats something it should not have like a peice of fencing, it lodges here in the Recticulum. However, the contractions of the reticulum can force the object into the peritoneal cavity where it initiates inflammation. Nails and screws can even peroferate the heart. The grass that has been eaten is also softened further in this stomach section and is formed into small wads of cud. Each cud returns to the cows mouth and is chewed 40 – 60 times and then swallowed properly.
3. The Omasum – this part of the stomach is a ‘filter’. It filters through all the food the cow eats. The cud is also pressed and broken down further.
4. The Abomasum – this part of the stomach is like a humans stomach and is connected to the intestines. Here, the food is finally digested by the cows stomach juices and essential nutrients that the cow needs are passed through the bloodstream. The rest is passed through to the intestines and produces a ‘cow pat’.
_URL_0_
| [
"Cattle are ruminants, meaning their digestive system is highly specialized to allow the use of poorly digestible plants as food. Cattle have one stomach with four compartments, the rumen, reticulum, omasum, and abomasum, with the rumen being the largest compartment.\n",
"Although the precise shape and size of th... |
relevant to the guy getting his artery pinched, how does the body cope with the constant building pressure through that artery with nothing giving back? | No, that's just one of many arteries in the body. Pinched shut, the highest the pressure can get in that artery is the pressure the heart can produce. | [
"Detecting pressure changes inside an artery from the outside is difficult, whereas volume and flow changes of the artery can well be determined by using e.g. light, echography, impedance, etc. But unfortunately these volume changes are not linearly correlated with the arterial pressure– especially when measured in... |
How do computer components keep track of timings between all of the systems of components? | Generally speaking they don't. There are drifts between components. What is important is that when they access a common bus they latch the clock of the common source [e.g. your PCIe clock].
There are collisions all the time on most buses, that's why they build in mechanisms to detect them and work around.
| [
"For a computer application the timing was still critical, but for a different reason. Conventional computers have a natural \"cycle time\" needed to complete an operation, the start and end of which typically consist of reading or writing memory. Thus the delay lines had to be timed such that the pulses would arri... |
Is sugar unhealthier when refined? | In fact, almost all brown sugars are made by adding molasses to refined white sugar, so as to more carefully control the resulting product. It will contain the same residual chemicals as white sugar. Unrefined sugar such as [muscovado](_URL_0_) is considerably harder to come by (YMMV. Try organic food stores).
Refining agents for granulated sugar, which is the most common, are typically phosphoric acid and calcium hydroxide. These absorb and entrap impurities then float to the top, where they are skimmed off. The sugar liquid goes through active carbon filtering afterward. While phosphoric acid has been linked to lower bone density in some studies, the evidence is somewhat sketchy. Moreover, it's presence in granulated sugar is very small. Granulated sugar is more than 99% pure sucrose. Many foods and soft drinks contain phosphoric acid as well. If you are worried, make sure you get enough calcium (milk is a good source) and you should be more than fine.
Sulfur dioxide is used to create what is called Mill white sugar. It doesn't remove impurities but "bleaches" the sugar instead. You won't usually find this unless you live in an area where sugar cane is grown, since this type of sugar doesn't store or ship very well. Sulfur Dioxide is also used in wine making and as a preservative, and as far as I know has no significant ill effects in the quantities present in sugar. | [
"Desserts with high sugar are commonly consumed for hedonistic rewards, especially among women. However, high sugar intake tends to increase risk of obesity, type 2 diabetes, hypertension, cardio-metabolic diseases and compromised oral health. Instead, research showed that honey is beneficial to health with its \"g... |
the scene in trading places with dan ackroyd and eddie murphy where they drive the stock price down and make millions of dollars while at the same time bankrupting the duke brothers. how does this work? | Recent thread on this: _URL_1_
Older thread on this: _URL_0_
My Answer from older thread:
/u/Pobody is right, but to clarify a bit, here's the stages (numbers are made up, just to illustrate):
1.) **That morning** - The Dukes have a fake crop report, saying that there is an orange shortage. They take out a short term loan so that they can buy orange futures at the current price. Say the price is $10, because people are unsure of whether there will be a shortage.
2.) **That afternoon** - Murphy and Akroyd show up. The price now is at $15, because the Dukes, and many others following the Dukes, have been buying all day, driving up the price. Murphy and Akroyd start to SELL. They don't own any shares (or own just a few), but that's alright, since they don't have to "settle up," meaning actually give the shares they "have" to the person buying, until the end of the day.
3.) **Just before the bell** - the crop report comes out. There is no orange shortage. Now, the price drops from $15 to $5, since everyone knows there are too many oranges, and so everyone starts selling. Once the price gets low enough, Murphy and Akroyd start to buy, which is easy, since everyone else is trying to sell. They buy enough to cover the sales they made earlier in the day, and pocket the difference (15-5 = $10 per share). The Dukes, on the other hand, are stuck. They sell what they can, but every sale is a loss.
4.) **after the bell** - the Dukes haven't made enough to cover their short term loans. They are bankrupt.
5.) **way after the bell** - Murphy's unrelated, identical twin, a wealthy African Prince, happens upon the Dukes living on the street, gifts them tens of thousands of dollars. they are back. | [
"Algorithmic and high-frequency trading were shown to have contributed to volatility during the May 6, 2010 Flash Crash, when the Dow Jones Industrial Average plunged about 600 points only to recover those losses within minutes. At the time, it was the second largest point swing, 1,010.14 points, and the biggest on... |
How does hilbert spaces describe states of systems? | In quantum mechanics, the state of a system is specified as a vector in a Hilbert space. Hermitian operators on the Hilbert space are associated with observables, in that their eigenvalues are interpreted as the possible outcomes of measuring the observable.
The other key interpretation bit is as follows. Suppose that we are given an orthonormal basis of the space consisting of eigenvectors of some Hermitian operator A. Then consider a general state and write it in components in this basis. Then (ignoring degeneracy) the mod squared of the component for some basis vector is interpreted as the probability that measuring the observable for A will yield the eigenvalue corresponding to that basis vector.
I should also mention that states in quantum mechanics evolve in time via a unitary operator, that is, there is some set of operators {U(t)} for t \in R (with lots of constraints, including some form of continuity/smoothness) such that U(t) acting on the state of the system at time 0 gives the state of the system at time t. This is critical because unitary operators preserve norms. States in quantum mechanics are required to have norm 1 (for the most part) because of the probability interpretations, i.e. the probability of getting *something* in a measurement must always always 1, so having non-unitary time evolution would result in something roughly like disappearing particles.
(Aside: there's also a picture where the states are static and the operators evolve in time, but that's completely equivalent.)
Also, at least in the prevailing interpretation of quantum mechanics, measuring an observable results in the system immediately changing its state to an eigenstate of that observable. | [
"In the theory of discrete dynamical systems, a state space is the set of all possible configurations of a system. For example, a system in queueing theory defining the number of customers in a line would have state space {0, 1, 2, 3, ...}. State spaces can be either infinite or finite. An example of a finite state... |
Is it possible to reflect or focus gravity with some kind of lens or mirror? | Yes, but we don't really have the technology to do that. Here's an example of gravitational lensing, [this picture](_URL_0_) of a distance quasar known as the Einstein Cross shows what seems like 4 copies of it due to the light being bent on it's way to Earth and then continuing onward. [Here's an artist's rendition of Gravitational Waves recently discovered around binary system J0651](_URL_1_). | [
"The use of mirrors avoids chromatic aberration but they produce other types of aberrations. A simple spherical mirror cannot bring light from a distant object to a common focus since the reflection of light rays striking the mirror near its edge do not converge with those that reflect from nearer the center of the... |
When did testing new hires for drugs become standard practice, and why? | Alrighty guys, because I've already had to remove ten comments similar to this, I'm going to leave a top-level mod post here. Please remember when posting here that this is not /r/Politics. We are not interested in contemporary politics, your opinions on current policies of countries, two word answers, one line answers, etc. [For more info on what makes a good answer, please see here.](_URL_0_) If you're interested in our [rules,](_URL_1_) there's a link in the sidebar for your perusal.
Have a great day :) | [
"In 1967 the IOC began enacting drug testing protocols. They started by randomly testing athletes at the 1968 Winter Olympics. The first Winter Games athlete to test positive for a banned substance was Alois Schloder, a West German hockey player, but his team was still allowed to compete. During the 1970s testing o... |
what were the united states democratic party's general views on gun control in the early 90s? | I'm not a historian, but they were very pro gun control legislation.
The Brady Bill finally came into existence in 1993 after a long fight with gun rights opponents over it's provisions. Interesting enough it was the Pro-gun side that wanted the background checks we currently have included.
The "assault weapon ban" was passed in 1994. Some political pundits blame that legislation for the Democrats losing control of congress.
President Clinton also signed an executive order that made all gun dealers "have a storefront", thus adding a huge expense to gun dealers and especially gunsmiths who had a machine shop in their basement. FFL's fell Approx. 80% in the decade after this order.
Basically, the views then echoed the recent views held. Although there was a mellowing of the views or at least less of a desire to push them after backlash was felt from the AWB, and that could be a possibility again after the results from the recent election. | [
"After election losses in 2004, the Democratic Party reexamined its position on gun control which became a matter of discussion, brought up by Howard Dean, Bill Richardson, Brian Schweitzer and other Democrats who had won in states where Second Amendment rights are important to many voters. The resulting stance on ... |
Did wooden sailing ships get struck by lightning and catch on fire all the time? Furthermore, later in the age of sail, did magazines explode from this? | It is by chance I have a paper (which is unfortunately for the rest of you in Croatian language) that tried to round up notes in official chronicles and ships logs of any mention of lighting strikes in the Adriatic sea for the period of 1300-1800. Most of the notes are just mentions of storms in passage, but some are recounts of tragic events like lightning hitting tall buildings like church towers, often with tragic consequences for bell ringers and clergy inside. Forts would also be hit, and occasionally stored powder inside would explode with horrifying consequences for the surrounding area.
A lot of notes are about ships, but most just noting surviving storms unharmed: But luckily (or unluckily for people involved) some do mention ships being directly hit by lightning strikes. Let's recount the mentioned:
In 1497 a very brief note in a ship's log says lightning struck the top of the mast. The crew despaired and thought the ship would be lost, yet it appears it was successfully managed, even though we have no extra description of what transpired.
In 1501 a note from local chronicles from the island of Hvar said a galley passing by got struck by lightning in the mast and had to get a new mast from the island.
In 1530, location unclear, there is a note that a mast of a ship was destroyed by lightning, and the ship asked to get a replacement mast.
In 1545, events log that a ship off the coast of southern Italy was struck twice by lightning, but this time in the stern, making it burst into pieces and hit the coastal reefs.
An event near Kotor in 1570 describes an event very close to your hypothetical scenario. An anchored commanding galley was struck by lightning, causing the "forty-year-old, dry wood" to burst into flames, spreading to rigging and sails, until it reached powder and ammo and blew the ship up into pieces.
The crews are recorded as being very frightened of lightning striking, even giving birth to several superstitions, like the recorded belief that striking axes in the mast would protect it from strikes, which was mentioned in these 16th-century notes.
---
To move forward in time a bit, there is a paper from 1762, a time of tall ships, discussing ways to prevent lightning strikes. In it, there are few descriptions of lightning strikes. The most detailed is the short description of ship Harriet which apparently got struck by lightning that "split into pieces" her main mast, main topmast and topgallant mast, made some damage to the bulk-heads, beams, hull, and other parts, as well as set fire to rigging and created much smoke, making crew believe there was a fire. If there was (it appears not) the crew extinguished it anyway. There is also a short note on a ship Bellona, whose main mast got split into pieces.
For even latter period we have a document by Harris from all the way back 1838. In the paper, the appendix lists damages by lightning to ships of Royal Navy in the years 1793-1830s. It records 174 cases of damage by lighting and concludes:
> From about one hundred cases in the above list; the particulars of which have been ascertained, it appears that about one half the ships struck by lightning, are struck on the main-mast; one quarter on the fore-mast; one-twentieth on the mizen-mast, aud not above one in a hundred on the bowsprit.
> About one ship in six is set on fire in some part of the masts, sails, or rigging.
In one half the cases, some of the crew are either killed or wounded, or both; the numbers are 62 killed, 111 wounded; this is exclusive of one case in which nearly all the crew perished; of twelve cases in which the numbers killed or wounded have been set down as several or many. In these 100 cases there were damaged or destroyed 93 lower masts, principally line of battle ships and frigates, 83 top-masts, 60 top-gallant masts.
In one-tenth of these cases, the services of the silips were urgently demanded.
Looking at the list, only one frigate of 44 guns was totally destroyed by catching fire after getting struck.
---
The above events are hardly enough to paint a complete picture, but we can make some conclusions. While ships more often passed through storms untouched by lighting, it was quite possible to be struck. This would be very dangerous, but it seems most damages to the ship was confined to the splitting (or bursting into pieces) of the mast. A serious setback, but one that could be handled by getting a replacement mast. More threatening for the entire ships was the possible start of a fire, as fire was always very dangerous on a ship, especially wooden ones. Yet in this small dataset, we luckily see very few such cases where fire has spread uncontrollably to destroy the ships. In most cases the fire was contained, or limited to less dangerous parts of the ships. For memebers of the crew, this was a thin comfort as even without fire the damage could be severe enough to wound or kill a considerable number of the men onboard.
---
Sources:
Kužić, K.. "GRMLJAVINSKE OLUJE, UDARI GROMA I VATRA SV. NIKOLE U HRVATSKIM PRIMORSKIM KRAJEVIMA (14.-18. st.)." Hrvatski meteorološki časopis, vol. 47, br. 47, 2012, str. 69-97. _URL_1_.
Watson, William. “Some Suggestions Concerning the Preventing the Mischiefs, Which Happen to Ships and Their Masts by Lightning; Being the Substance of a Letter to the Late Right Honourable George Lord Anson, First Lord of the Admiralty, and F. R. S. by William Watson, M. D. F. R. S.” Philosophical Transactions (1683-1775), vol. 52, 1761, pp. 629–635. JSTOR, _URL_0_.
W. Snow (William Snow) Harris. State of the Question Relating to the Protection of the British Navy from Lightning, by the Method of Fixed Conductors of Electricity. 1838. JSTOR, _URL_2_. | [
"Ship breaking, particularly if the ship had been involved in significant events such as the Battle of Jutland, resulted in much of the wood from the ship being turned into miniature barrels, letter racks, and boxes, with small brass plaques attached announcing, for example, \"Made of teak from HMS \"Shipsname\", w... |
Why were armies so much larger in the Punic War than they were during the Thirty Years War? | Is there a particular reason you picked those specific conflicts, as opposed to classical vs medieval? For one thing, we could have chosen much bigger Septimus vs Clodius Albinus (estimated 150,000-300,000 on EACH side) | [
"For the vast majority of the period of its existence, the Polybian levy was at war. This led to great strains on Roman and Italian manpower, but forged a superb fighting machine. During the Second Punic War, fully two-thirds of Roman \"iuniores\" were under arms continuously. In the period after the defeat of Cart... |
If Photons have no mass, then how does sunlight exposure give me Vitamin D? | The photons don't carry Vitamin D. Rather, the ultraviolet rays of light penetrate the first few layers of the epidermis to reach the stratum basale and stratum spinosum. In these layers of the skin, the cells contain 7-dehydrocholesterol which, when hit by ultraviolet rays of light, turn into a form of Vit D.
I don't understand the physics behind how a photon actually converts a compound into something else, however. They don't teach us that in medical school. | [
"The ultraviolet radiation in sunlight has both positive and negative health effects, as it is both a principal source of vitamin D and a mutagen. A dietary supplement can supply vitamin D without this mutagenic effect. Vitamin D has been suggested as having a wide range of positive health effects, which include st... |
Can a turtle feel something touch its shell? | A turtles shell is part of its bone structure and is used for many metabolic processes (like metabolic depression during anoxic conditions under water), so yes they can. It is quite sensitive because of the nerves that are required for those processes. | [
"Blanding's turtle is a timid turtle and may plunge into water and remain on the bottom for hours when alarmed. If away from water, the turtle will withdraw into its shell. It is very gentle and rarely attempts to bite. It is very agile and a good swimmer.\n",
"Another safety concern is interaction and contact wi... |
why are salmon and tuna more 'meaty' than white fish like cod/haddock/sea bass? | They both have higher fat content than the milder flavored white fleshed fish. Tuna more so than salmon. | [
"Salmon is a common food classified as an oily fish with a rich content of protein and omega-3 fatty acids. In Norway – a major producer of farmed and wild salmon – farmed and wild salmon differ only slightly in terms of food quality and safety, with farmed salmon having lower content of environmental contaminants,... |
why is it when i'm cold my jaw can shiver ridiculously fast, but when i'm warm i can't physically force myself to shiver my jaw that fast? | You can.
However, what you're doing is most likely different, when you attempt shiver manually, it sounds like you're trying to contract your muscles rapidly. Shivering isn't exactly that, it's closer to simply vibrating your muscles, it's not a full contraction. | [
"There has yet to be any peer-reviewed research on the topic. The most plausible theory, is that the shiver is a result of the autonomic nervous system (ANS) getting its signals mixed up between its two main divisions:\n",
"Individuals who scored higher on this factor typically displayed a lack of any movement, f... |
what does it mean to compile code? | As you may know, everything in a computer is represented by a series of 1's and 0's (which themselves represent high and low voltages on transistors, but that's a topic for another time). When the computer runs a program, the program itself is made of a bunch of 1's and 0's.
However, since we still need humans to write our programs, putting everything in 1's and 0's (called machine language) would be very difficult. So we made higher level languages like Java and C# to write code in. These languages look a lot more like English, so they're a lot easier to write and maintain.
When you compile code, the compilor (usually another program) takes the program the human wrote, and converts it into the program the computer can understand (i.e. converts from Java to machine language). The very short version could be, yes, compile means to make the code executable.
Something you may run into is people saying code does or does not compile. This means the compilor they used checks to make sure their program is written correctly according to the rules of the programming language. For example, most programming languages make you put a semicolon (;) at the end of every line. A very common mistake is to forget that semicolon, so when you try and compile the compilor gives you an error.
It's also important to note that just because the code compiles doesn't mean it works. It's sort of like how 3 + 4 < 5 is an equation that has the right form, but it is incorrect. | [
"Compile is a program that downloads, unpacks, compiles source code tarballs, and installs the resulting executable code, all with a single command (such as codice_25) using simple compilation scripts known as \"recipes\".\n",
"BULLET::::- A subfield of computer programming – process of designing, writing, testin... |
How profound was the influence of Jazz and Blues on American Culture in the twenties? | I'm not sure how we could give you a gauge of just how profound the impact was, but for reference the death of David Brubeck made the front pages of the both the New York Times and Washington Post among other today. He first splashed onto the music scene in the 1950s. Some would argue that jazz music is a uniquely American phenomenon and one of the only thoroughly American forms there is.
The first thing to consider is that even defining jazz is highly controversial. Some believe in a broadly inclusive definition of jazz that can even include elements of hip hop. Others believe that bebop is quintessential jazz music and that music that get labeled jazz that came after is just watered down pop music. The Ken Burns Jazz series more closely reflected the latter view, which is why I always warn folks that that particular documentary series is too one-sided to consume without also looking into other viewpoints.
It would be tough to underestimate Jazz's cultural impact because the music often went hand-in-hand with other social and cultural issues. Jazz music grew up surrounded with controversy and there was a good deal of reactionary push-back against it. Jazz clubs were among some of the earlier integrated public gatherings. African American communities used jazz as a form of high art; some wanted to develop a distinct black culture while others thought that jazz as an art form could help break down racial barriers. Jazz and prohibition were part of a unique subculture during prohibition. Jazz was highly contentious within the music community because it was a pretty radical departure from the western tradition. The Nazis thought it was influential enough to label it "degenerate art" and prohibit it. The U.S. government sent jazz musicians overseas as cultural emissaries and it was used as part of the U.S.'s strategy to undermine soviet regimes. Early in his career Louis Armstrong was labeled by some as an Uncle Tom, but by the 1950s he was a forceful civil rights voice.
The contemporary literature can give you great insight into some of these issues and Robert Walser's collection of articles in *Keeping Time: Readings in Jazz History* is a great starting point to gain a cultural understanding.
edit: This post doesn't really answer the question, but since nobody else answered I was hoping that some of the themes I mentioned could spur some discussion by some professional historians. | [
"The 1920s brought new styles of music into the mainstream of culture in avant-garde cities. Jazz became the most popular form of music for youth. Historian Kathy J. Ogren wrote that, by the 1920s, jazz had become the \"dominant influence on America's popular music generally\" Scott DeVeaux argues that a standard h... |
why do antivirus programs identify videogame cracks as dangerous viruses or trojans? | It depends. With some code, especially in some games, it can be misidentified as a virus due to the fact it is similar to a virus' code, marking it as a virus or trojan. On top of this, some malicious uploaders put viruses or trojans into your download, so that, when you run it, it activates the malicious code. Other times they are false-positives, where the anti-virus program flags it as a virus when there is nothing wrong with it. Moral of the story, don't get PC game cracks if you want to be safe, and legal, but if you want to, I will not stop you. | [
"Most anti-virus software and intrusion detection systems (IDS) attempt to locate malicious code by searching through computer files and data packets sent over a computer network. If the security software finds patterns that correspond to known computer viruses or worms, it takes appropriate steps to neutralize the... |
What's the fewest celled multicellular life? Are there any 2-celled organisms? | There certainly is something in between: a vast array of small creatures. The simplest of which and the smallest integrated multicellular organism is the [Tetrabaena Socialis](_URL_1_). This volvocid forms a colony of four ovoid cells, each with two equal flagella, two contractile vacuoles, and a pyrenoid and a red eyespot within a single green chloroplast.
Colonial cells are attached to each other by the protuberances of their cellular sheaths and are also held together by a gelatinous capsule surrounding the entire colony.
[Here](_URL_0_) is a video of one swimming with it's eight tails, really cute. | [
"\"Parakaryon myojinensis\" (\"incertae sedis\") is a single-celled organism known by a unique example. \"This organism appears to be a life form distinct from prokaryotes and eukaryotes\", with features of both.\n",
"The simplest definitions of \"multicellular,\" for example \"having multiple cells,\" could incl... |
Why is it that in airliners, the cockpit windows are polygonal whereas the passenger windows have to be round to avoid stress concentrations? | Cockpit windows are designed to withstand bird strikes and are much stronger than passenger windows. | [
"This distinctive style of bodywork has a downward-sloping front window bay on the upper deck, with both top and bottom edges angled downwards. The side windows are square-cornered. A large double-curvature upper deck windscreen (either single-piece or two-piece) is one of the most distinctive features.\n",
"Wind... |
In 1939, the eastern half of Poland was occupied by the Soviet Union. What was life like under the Soviet occupation and what happened to the previously Soviet occupied territories after their liberation from the Germans? | During the Soviet occupation, one of the first things they did was to eliminate any chance of resistance to their occupation. The NKVD already had a large number of Polish Army officers and enlisted in prisoner camps, and to these numbers added university professors, lawyers, police officers, priests, politicians, essentially anyone who could become the focal point of resistance or who could inspire others to resist. Some were just “capitalists” such as factory owners, but the majority was part of the social and civil fabric and could become potential sources of resistance. The NKVD at one point had approximately 500,000 Poles in prison camps in Poland. The NKVD proceeded to liquidate the most troublesome @22,000m of which 14,000 were captured military or police officers. Enlisted soldiers in many instances were shipped to Siberia to provide labor gangs. The executed were then collected and buried in several mass graves in the Katyn Forrest. These graves would remain hidden until the Germans overran the area during their invasion eastward. There are another estimated 130,000 executed by the Soviets during the occupation, on top of the Katyn incident. The Katyn incident is the most notorious. The Soviets justified in that Poland was never a country, just merely a rebellious extension of Belarus and Ukraine, so captured Polish army members were not afforded the rights of POWs and were simply criminals.
Initially the occupation was resented by Poles, but welcomed by ethnic Ukrainians and other minorities within the Polish boundaries. This ended quickly as it became clear the Soviets were not going to allow these groups any measure of self-determination, and would be suppressed like the Poles. The Soviets begain a process of de-Polandizing Poland. Disbanded the government, replaced the currency, the Soviets also engaged in widespread looting of Polish industry, shipping the machinery east, as well as plundering Polish national treasures, as well as petty looting of the populace. No public organizations were allowed to exist, the university and the school system had any elements of Polish culture stripped from them and were reorganized to be Soviet institutions. Sexual violence by Soviet troops appears to also have reached epidemic levels among Polish women, but historians have had only scattered and fragmented accounts and cannot accurately place a number, or even really give an accurate guess on the number of victims. (The Red Army would repeat this during their return to Poland as they drove West into Germany years later.) The Soviets began mass deportations in several cities, as well as deporting those arrested and convicted of anti-revolutionary activity or crimes against the Soviet Union. Roughly a million or so Poles were deported to Siberia and Kazakhstan. The land was reorganized according to Soviet guidelines and collectivized, as were all remaining industries. Basically, the Soviets were doing everything possible to annex and integrate the captured territory into the Soviet Union.
*Between Nazis and Soviets* - Jan Chodakiewicz
*Katyn* – Paul Allen
*Poland's Holocaust* - Tadeusz Piotrowski
| [
"In September 1939, at the outbreak of World War II and in accordance with the secret protocol of the Molotov–Ribbentrop Pact, Poland was invaded from the west by Nazi Germany and from the east by the Soviet Union. Volhynia was split by the Soviets into two oblasts, Rovno and Volyn of the Ukrainian SSR. Upon the an... |
i have a microwave oven that has a spinning carousel that turns clockwise sometimes and counterclockwise at others with no discernible pattern. why and how does it do this? | Cheap motor. It will continue spinning in either direction, and starting direction depends on the exact time it's started (from the alternating power supply) | [
"Thus, in Nordström's theory, if the nearly elliptical orbit is transversed counterclockwise, the long axis slowly rotates \"clockwise\", whereas in general relativity, it rotates \"counterclockwise\" six times faster. In the first case we may speak of a periastrion \"lag\" and in the second case, a periastrion \"a... |
psychologists, psychiatrists, and other experts of reddit, what makes one an addict? | Questions similar to this come up fairly often, and I always point out the following:
**Addiction** is *not* the same thing as **Physical Dependency**.
If you are physically dependent on a substance (such as nicotine or alcohol) then it is 100% the substance you are physically dependent on. That's *not* "in your mind", as it were. Your body gets used to the substance, depends on it, and if you stop you have symptoms that can range from bing irritable to life-threatening conditions.
Now, in *addition* to that, you also form a mental addiction. A habit. We are creatures of routine; classical conditioning works extremely well with Humans. We get used to stuff like smoking after a meal or drinking while watching TV, to the point where removing one makes the other feel uncomfortable.
Please note that mental addiction need not be to a substance. It can really be to *anything*. Playing video games for hours upon end after work/school, for example.
It can also *easily* apply to things people will claim are not addictive (I'm looking at you, marijuana). The truth is it might not cause physical dependency, but it absolutely can cause addiction.
As to what makes one more susceptible to addiction - we're not absolutely sure. Again, Humans in general like routine and habits, so that's kind of built-in. We also have a reward center in our brain that likes to release dopamine when something good happens - this helps addiction form (think gambling addiction: your brain releases dopamine when you win, which feels good, so you keep gambling, chasing the dopamine high!)
There are some genetic traits we're pretty sure affect this. For example, people who's brain is a bit liberal with dopamine are in a higher risk group.
But like any other genetic disposition, there are likely numerous other factors towards or against it. For example, you may be predisposed to high blood pressure, but you also stay in good shape and eat healthy, so you *don't* have high blood pressure.
As for psychological/sociological markers, I'm afraid there's no real answer. Addiction strikes across cultures, across economic classes, ages, genders, races, you name it. You can use statistics to say who's more likely to become addicted, but that doesn't work on individuals.
As for real-world applications, one thing seems to be true - addicts need to *want* to kick an addiction.
After that, again, it's a very individual process. Finding out the reasons that lead one to their addiction is key, and then figuring out ways to avoid them. Whether that means "Stay away from bars" if you're an alcoholic, "Find new friends" if your friends are your catalyst, etc. There's not one magic treatment that works for everyone - that's why there are many different psychological models that therapists can use, and many use a combination of several. | [
"An addict is more prone to depression, anxiety, and anger. Both the addict's environment, genetics and biological tendency contribute to their addiction. People with very severe personality disorders are more likely to become addicts. Addictive substances usually stop primary and secondary neuroses, meaning people... |
Why do planets have axial tilts which deviate greatly from the normal of their orbital plane? | I am no astronomer, but in the off chance this doesn't get answered, I'll give it a go.
Their orbit around the sun, as you said, is planar. However, the gravitational force acting on each planetary body is relatively uniform. That is to say, the gravity pulls no more on the poles than anywhere else on the planet. The tilts, therefore, are not influenced by the sun's gravitational well. The planets' individual rotations and original tilts are due to formative collisions and other influencing forces. | [
"Planets rotate at varying rates and thus may take a slightly oblate shape because of the centrifugal force. With such an oblate shape, the gravitational attraction will deviate somewhat from that of a homogeneous sphere. This phenomenon is quite noticeable for artificial Earth satellites, especially those in low o... |
When DNA is copied where do the new nucleotides that create more DNA come from? | Nucleotides can be synthesized "de novo" from precursor molecules (obtained from the breakdown of food, for example). The major organ involved in this process is the liver. However, nucleotides can also be [recycled](_URL_0_) through a process that synthesizes nucleotides from the components of degraded nucleotides. | [
"When DNA is copied, the two strands of the old DNA are pulled apart by enzymes; then they pair up with new nucleotides and then close. This produces two new pieces of DNA, each containing one strand from the old DNA and one newly made strand. This process is not predictably perfect as proteins attach to a nucleoti... |
what are the main features of the unity engine? its advantages and disadvantages against other game engines? | The Unity Engine is a 3d based engine used primary for games.
The Unitiy's Engines advantages are
1.) Run on almost every platfrom (Unreal 3 for example only runs on PC, Window, PS3 with a Lite version running on Iphone)
2.) Comes with a easy to use user interface that is visual and lower the amount of programming in contrast to say the Quake Engine. (I believe Unity is a LUA friendly)
3.) Well supported in contrast to say the horrible engines you haven't heard about.
4.) Cheap, in comparision to the Unreal Engine which is significantly more expensive to license for games that you are selling.
Unity's disadvanatages are.
1.) Because it runs on so many platfrom it's difficult for the system to be truly optimized for one platform. If your look to do super high performance things you will have more difficult in contrast to say your own engine that you've developed.
2.) Doesn't have the peneration of say Flash. If you want people to download and play your game in a browser more people will have Flash then Unity.
3.) As with all engines your still abstracted from what your doing. If you make your own Engine then you'll have more control and will fight with the engine less. For example using OpenCL in the Unity would be difficult.
4.) Not as cheap as Open Source or writing you own in something like DirectX or OpenGl .
:P Innovating gameplay mechanics sound cool. But in reality innovative game mechanic actually means "I really enjoy Algebra, and Trig." | [
"Unity is a cross-platform game engine developed by Unity Technologies, first announced and released in June 2005 at Apple Inc.'s Worldwide Developers Conference as a Mac OS X-exclusive game engine. As of 2018, the engine had been extended to support more than 25 platforms. The engine can be used to create three-di... |
What is it that actually transfers light in a perfect vacuum? | You do not need particles to move for energy to exist. Light consists of an oscillating electric field that produces an oscillating magnetic field that produces an oscillating electric field and so on. These fields happily exist separately from particles. | [
"In nature, a light source emits a ray of light which travels, eventually, to a surface that interrupts its progress. One can think of this \"ray\" as a stream of photons traveling along the same path. In a perfect vacuum this ray will be a straight line (ignoring relativistic effects). Any combination of four thin... |
i've been hearing a lot on reddit lately about how the baby boomer generation "screwed over" the generations to follow. what specifically have they done that was wrong? it seems like they were just dealt a better hand by circumstance and weren't able to control the bad things to follow. | Because of the size of their generation, the Boomers caused a lot of disruptions in society as they passed through, especially in the education system in the 1950s and 1960s, and the healthcare system today. There simply wasn't the capacity for them at the time and those systems were strained.
Most of America's current political leaders are also Boomers, so the whole generation gets sort of conflated with "those grey haired bastards that aren't doing anything about tuition hikes or youth unemployment". | [
", it was reported that, as a generation, boomers had tended to avoid discussions and long-term planning for their demise. However, since 1998 or earlier, there has been a growing dialogue on how to manage aging and end-of-life issues as the generation ages. In particular, a number of commentators have argued that ... |
Does applying water or ice to your blood pulses actually cool you off? | The most effective places to place ice are neck (carotid/jugular), armpits (axillary) and groin (femoral). It's simple physics that these areas have the largest volume of blood circulating closest to the surface of the skin and thus dissipate heat more effectively. | [
"Applying ice, or even cool water, to a tissue injury has an anti-inflammatory effect and is often suggested as an injury treatment and pain management technique for athletes. One common approach is rest, ice, compression and elevation. Cool temperatures inhibit local blood circulation, which reduces swelling in th... |
what are spectral lines and how do we use them to determine what light has passed? | If you direct light through a prism, you can spread it out and look at all the different frequencies it's composed of.
If you look very closely, you'll notice that certain frequencies are ["missing"](_URL_0_) (or at least severely reduced in intensity).
That means that somewhere between when this light was emitted, and when you looked at it, that particular frequency was absorbed by something.
Every material has a unique absorption spectrum, so you can tell what kind of materials the light has passed through. | [
"Spectral lines are the result of interaction between a quantum system (usually atoms, but sometimes molecules or atomic nuclei) and a single photon. When a photon has about the right amount of energy to allow a change in the energy state of the system (in the case of an atom this is usually an electron changing or... |
Earlier today i saw two clouds going in opposite directions, how is this possible ? | Air at different elevations is nearly always traveling in different directions and speeds, your clouds were in two different layers. The motion of air is anything but uniform at all elevations.
| [
"Two common cloud patterns seen during this time are a chinook arch overhead, and a bank of clouds (also referred to as a cloud wall) obscuring the mountains to the west. It appears to be an approaching storm, but does not advance any further east.\n",
"These patterns are formed from a phenomenon known as a Kármá... |
How did it came about that we do not call Japan an Empire today even though its current head of state Akihito is still officially referred to as "Emperor"? | I will speak in very broad generalizations here.
Japan was a very famous, literal empire in the '40s, and after their capitulation in WWII, their empire was dismantled, both their territorial holdings, and most of the functioning government.
The emperor was not dethroned, for political reasons. That's why Japan has an emperor "left over" so to speak.
"Empire" is a vaguely defined word that comes with serious baggage. The big problem is that most emperors and kings of the world aren't actually called "emperor" or "king", these are translations of foreign titles of foreign institutions. But they're translations of convenience, kings are monarchs that rule big lands, emperors rule even bigger lands.
However, Western concept of the emperor is fairly cohesive. We draw our definition from the Roman emperors, who were the martial and administrative nuclei of the overwhelmingly powerful Roman Empire (For the most part). But because the formative years of mass politics were in the 19th and 20th centuries, we also associate the word empire with the vast, powerful, wildly expansionist powers of that era (Who were mostly ruled by emperors using that title to evoke Roman magnificence)
Now back to Japan. Japan has had a figure that we call emperor since at least 500 AD (The earliest emperors are sketchily recorded). While the Roman emperors were below gods and politically dominant, the emperors of Japan were heads of the Shinto faith, and for quite a long time merely figureheads for *shoguns. The Japanese word for the Emperor of Japan is *tenno
Quite obviously, these offices aren't the same. But in the 19th century, a Japanese state became a vast, powerful, expansionist power. It's head of state was the *tenno, who Westerners then called emperor.
Why are there no more empires in the West? Most of the Western emperors had their empires dismantled, or were replaced by republicans (any non-monarchical governments).
The British monarch is a secular, apolitical office, and its imperial title was 'Emperor/Empress of India". When India became independent in '48, they lost that title. No more emperor, and with decolonisation, no imperium to rule.
The Russian monarch was a semi-religious title with absolutist political power, but the last Emperor was overthrown in violence. The Russian Revolution was organised around explicitly deposing the Emperor of Russia to be replaced by a People's Government, and they succeeded. The great imperium gained by Tsarist Russia was mostly still controlled by Russians though.
The Japanese monarch is a religious title, with constitutional powers. After WWII the secular governing body of Japan was deposed, and the remaining political power of the emperor was removed. But the US occupying force did not want to depose the emperor, because they believed the Japanese would not accept a foreign power abolishing their Religious leader. The *tenno remained.
Finally, it should be said the empires and imperialism do not require emperors. With Britain and Japan, for example, the administrators and governors of their empire was not actually the emperor themselves. You've probably heard of people referring to an "American empire", or a "business empire", and these phrases are simply meant to evoke a powerful institution with a heavily centralized nucleus of power. They do not require literal emperors.
Basically, an empire is as much a construct of our thinking as it is an actual title. Japan today does not act like an "empire", so we don't call it that. The Emperor of Japan was not the same as a Western emperor, we just translate *tenno as emperor.
| [
"Currently, the Emperor of Japan is the only head of state in the world with the English title of \"emperor\". The Imperial House of Japan is the oldest continuing monarchical house in the world. The historical origins of the emperors lie in the late Kofun period of the 3rd–7th centuries AD, but according to the tr... |
why do companies with a large amount of cash still issue debt? | Taking on debt spreads financial risk across a longer period of time.
If I shell out 100% today, I'm out 100% today, and 100% tomorrow of my investment goes south. I'm screwed the day after tomorrow.
If I shell out 2% today, I'm out 2% today and 2% for the next 4 years, so if things don't work out, I can continue to operate and pay my bills. | [
"There have been at least two cases of companies seeking to restructure their debt (i.e. pay creditors less), claiming that debt they had issued was not in compliance with sharia. In a 2009 court filing Investment Dar, a Kuwaiti company claimed a transaction \"was taking deposits at interest\".\n",
"In 2014, for ... |
why "everything" is one word and "every time" is two | Every time I hear this everyday question I wonder will I be asked it every day. | [
"In ordinary conversation, \"everything\" usually refers only to the totality of things relevant to the subject matter. When there is no expressed limitation, \"everything\" may refer to the universe, the world.\n",
"One can make the statement that \"anything\" is a specific word where \"everything\" can be seen ... |
why do some people find it hard to eat enough, while others over-eat? | Leptin sensitivity, insulin sensitivity, ghrelin and other hormones cause different appetite levels for different people. That's an oversimplification but basically leptin is one of the main hormones that puts the "brakes" on hunger. Thinner people have high leptin sensitivity and therefore recognize feelings of fullness more readily after eating. Overweight people develop resistance to leptin, leading them to feel hungry for longer. | [
"Difficulty eating is most often caused by difficulty swallowing. This symptom is common in people after a stroke, people with Parkinson's disease or who have multiple sclerosis, and people with dementia. The most common way to help people with trouble swallowing is to change the texture of their food to be softer.... |
How can you "see" your breath when it's cold? | The tempature drop from body temp to outside temp causes the gaseous water from your breath to condense to liquid forming tiny water droplets that refract light differently and cause the visual effect that we see when we breath out in the cold. | [
"In humans, the diving reflex is not induced when limbs are introduced to cold water. Mild bradycardia is caused by subjects holding their breath without submerging the face in water. When breathing with the face submerged, the diving response increases proportionally to decreasing water temperature. However, the g... |
How was the Dutch military rebuilt after the Second World War and what were the consequences for the Indonesian War of Independence only 2 years later? | The forces that were used in the Dutch East Indies were part of two groups. There was the "Mariniersbrigade" which was trained in the United States during the Second World War. It consisted of a few Dutch volunteers who were preparing for the war versus Japan, their primair goal was to liberate the Dutch East Indies. However, when Japan surrendered in 1945 and Soekarno called for independence, their purpose changed. Now, the brigade was used by the Dutch government for the war versus Indonesia.
The more famous Koninklijk Nederlands-Indisch Leger (KNIL) or in English the Royal Netherlands East Indies Army, was used during the Second World War versus Japan, in contrast to the Mariniersbrigade. Though no Dutch soldiers fought the Germans after the surrender that followed the bombing of Rotterdam, the war in Asia continued, with military oppositon towards the Japanese. Though many KNIL soldiers (they were Dutch but also native men!) were taken by the Japanese as a prisoner of war, many were still able to flee and continued the fight versus Japan, sometimes cooperating with the British, Australians and of course the Americans.
Thus the armies that were involved was well trained, it was not necessary to build anything from scratch. Nor did the hunger winter influenced the soldiers, since most were already in Asia when the hunger winter happened.
Sources:
Karel Davids and Marjolein 't Hart, De wereld & Nederland (Amsterdam 2011).
Pierre Heijboer, De Politionele Acties (Haarlem 1979).
| [
"The Japanese invasion and subsequent occupation during World War II ended Dutch rule and encouraged the previously suppressed Indonesian independence movement. In May 1940, early in World War II, the Netherlands was occupied by Nazi Germany. The Dutch East Indies declared a state of siege and in July redirected ex... |
how do tarrifs work? | So let's say that I'm building widgets in my factory in Canada. These are fine widgets. I make them for $70 each, and they sell (to stores) for $80. There are also factories in America that produce and sell widgets at around the same price. That puts us in competition; after all, people only need to buy so many widgets per year, but they do need widgets. You can't *not* have a widget, after all.
American shops buy widgets at around $80, then sell them on to the customer at $100. Everyone gets a profit, and because there's very little difference in cost, it doesn't really matter whether the widgets used are Canadian or American. Some people prefer one; some the other.
But say the President wants to boost the American widget industry. He can either do that by putting money into US widgets (either directly or via things like lowering their taxes to make it a more profitable venture), or by making Canadian widgets less attractive. He chooses the latter. He decides that from now on, anyone importing Canadian widgets is going to have to pay an extra $20 to get their widgets across the border. Here's the logic:
American stores now have a choice between buying American widgets for $80, or Canadian widgets for $100. Given that the market pretty much lets them sell widgets at or around $100, they're suddenly making *much* less profit on Canadian widgets. To make more profit on widgets, they either need to increase the price they sell Canadian widgets at (making them less attractive to consumers, driving them towards buying American widgets and increasing demand), or they need to stop buying Canadian widgets for resale, meaning that they'll have to buy American widgets instead. In the long term, if the price of importing widgets from Canada becomes too high, companies might choose to just produce widgets in the US rather than sending their widget-making jobs abroad. That's jobs for the US workforce, which means taxes for the US government. Either way, it's a win for the hardy American widget manufacturer *and* the wider population.
In theory.
*Except.*
There are a couple of things that can go wrong here. The first is that Canada does the same thing to American widgets, but also puts tariffs on American doohickeys and thingumabobs. Now the doohickey and thingumabob industry are pissed at you because you've just dragged them into a trade war that they wanted no part of; by trying to help one industry, you've hurt another.
The second is that some stores may not have access to American widgets to sell. If you sell the kind of widget that they only make in Canada, you're pretty much boned. All of a sudden, you're now not making a profit unless you sell your widgets at $120. You can't afford to keep the store open without it, but because people need widgets, they have to pay extra. Now you're just hurting the American consumer, because they're paying more for their widgets.
The third is that American stores don't *really* want to lose money, and may see a business opportunity. They may just start selling Canadian widgets at $120, but they may increase the price of American widgets too -- because after all, if you need a widget and the Canadians can't drop their prices (because of the tariffs keeping it artificially high), you're still going to have to spend the money. Why not make them spend $120 on a Canadian widget (giving you $20 profit) or $110 on American widgets (making you $30 profit)?
This is the most ELI5 version. There are lots of other things that can happen too. (Notably, a tariff often has the effect of devaluing the currency of the target population. That means that goods are cheaper when you buy them abroad, which may -- in some cases -- temporarily make it *more* profitable to buy Canadian widgets if the Canadian dollar takes a hit.) | [
"A tarpaulin ( , ), or tarp, is a large sheet of strong, flexible, water-resistant or waterproof material, often cloth such as canvas or polyester coated with polyurethane, or made of plastics such as polyethylene. In some places such as Australia, and in military slang, a tarp may be known as a hootch. Tarpaulins ... |
when a movie is said to have begun "filming", typically how long is this process vs. the rest of the movie making process? | Well that depends. If you have a stellar editor, than they might be able to finish up rather quickly, and you have a stellar crew, they might finish a scene in one wrap. But generally speaking, actually filming a movie takes alot longer than most people think. You usually end up filming one scene in a 12 hour work day. Think of scene in a movie you saw recently. It seems like the actor must have performed that scene very naturally in one take, but in reality, he probably said the same lines 100 times, each being shot from various angles and acted differently. Then comes the editing, which picks out the best version and angle of the previous 100 shots. The filming aspect could generally last anywhere from 1 to 6 months depending on the length and complexity of the film, and then the editing an additional 1 to 3. Of course these are just ballpark estimates as some films could take much longer for both filming and editing. (A film heavy in cgi effects would take much longer to edit) and of course these all depend on the scale of the production. (A set with 200 staff will be able to produce the same project much quicker than a set with 20 staff). But none of this is even taking to account the PR and marketing that goes in to play throughout the process, and most finalized films will take longer to come to the big screen because they will compete in various film competitions and do test screenings first. But to answer your question, the duration of each aspect depends on alot of different variables, making it a very difficult questions to answer. I would like to see a comment from someone who has worked on a numerous amount of feature films with a large production staff to see if they could give some average numbers at that size. | [
"The film took 3 years to make: one year of thinking and planning, one year of production, and one year to edit and finish it. The film was scripted in advance, though changes were made during filming and production. Of the three years, only six weeks were spent shooting on location.\n",
"Filming began in the Nov... |
Who paid for the early running water and electricity systems in America? How did they work? | This is not my area of expertise, but my grandfather had a role in rural electrification in Kansas, so I know a bit.
During the Roosevelt administration a program of rural electrification, supported by co-ops (many which still exist in some form today) brought power to the farms of the Midwest. It was a large undertaking, with one of the aims being to staunch the flow of people leaving rural communities for cities by creating jobs and improving quality if life.
_URL_0_
_URL_1_ | [
"The system is believed to be the first pump-powered water supply to be implemented in what is now the United States. The town of Boston, Massachusetts had a municipal water supply as early as 1652, but it was purely powered by gravity.\n",
"Electricity was available in 1905 and city water in 1929. Manufacturing ... |
Why did the British Empire collapse while the Soviet Union remained a superpower after WW2? | So /u/ThePutback wrote about the differences in how the nations were "devastated" in the war, but I wanted to expand on another difference between the British Empire and the Soviet Union:
The Soviet Union was the ideological leader of an increasingly significant portion of the world in the wake of WW2.
So while the British Empire physically possessed numerous colonies and protectorates across the world, the Soviet Union had the virtual **ideological ownership** of many nations and revolutionary groups all around the world.
This only grew as Europe de-colonized rapidly after WW2 when many new governments and revolutionary groups aligned themselves with Eastern bloc (regardless of how much adherence they had to Marxist/communist ideology).
Whether it was the split between the Koreas immediately after WW2, or the ideological struggle between the Vietnams split after the French withdrew in the 1950s, the wave of pan-Arabism in the 1950s and 1960s that was closely aligned with the Soviet Union, or the formation of People's Democratic Republic of Yemen after the British protectorate there ended in the late 60s, or the fight over Angola after independence from Portugal in the 70s... the Soviet Union possessed a massive amount of power with a large bloc of nations in the world throughout all the decades of the Cold War.
The British simply didn't have the manpower or financial situation to maintain such an extensive network of colonies, especially as de-colonization often ended up in bloody affairs in many places around the world. Furthermore, the backbone of the British Empire, the Royal Navy, could no longer compete with the US or even the Soviet navies.
In fact, by the end of WW2, the UK had already ceded domination of the seas to the United States and navies are very expensive. For instance, the US maintained at times during the Cold War over 16 fleet aircraft carriers simultaneously (over 24 of them in different configurations forms in 1960 alone), and by the end of the Cold War in 1991 had 14 supercarriers in simultaneous service.
In contrast, the UK retired its last fleet carriers using conventional catapult and arresting gear configurations in the 1970s. No new designs were bought or commissioned, and the UK nearly sold its remaining light carriers using Harriers until the Falklands War stopped their sale. Add on the humiliation of the Suez Crisis, and the UK finally pulling its last carrier out from Hong Kong in the 1970s, the end of the "East of Suez" era for British power projection was evident. And, without the ability to project power to defend its colonies and protectorates abroad, decolonization only hastened and many of those protectorates became aligned with the US, which filled in the role that the British once did (such as the end of protectorate status for the Trucial States, which would form Qatar, Bahrain, and the UAE, nations that have US military bases/forces stationed there). | [
"The consequence of fighting two World Wars in a relatively short amount of time, along with the emergence of the United States and the Soviet Union rise to superpower status after the end of World War II, both of which were hostile to British imperialism and along with the change in ideology led to a rapid wave of... |
why do progressive countries put their focus and resources on free healthcare and free education and not on free food, free clothing and free shelter? | Give a man a fish and he will eat for a day, teach a man to fish and you feed him for a lifetime.
Basically education and health care is a much more cost effective way to reach the same end goal. Plus if you provide shelter food etc free to everyone then lots of people might just stop working. | [
"Other countries have an explicit policy to ensure and support access for all of its citizens, to fund health research, and to plan for adequate numbers, distribution and quality of health workers to meet healthcare goals. Many governments around the world have established universal health care, which takes the bur... |
Why do certain instruments have to transpose to concert pitches? For example, why does a trumpet play a C instead of concert B-flat? Was this some sort of musical evolution? | I can answer this for the brass more convincingly than for the woodwinds, perhaps someone else can fill in those blanks.
Back before the valve was invented, composers would write music in a certain key. The trombone has a slide which enables it to change length at will, meaning it can play in Eb as easily as in F. But the Trumpet and Horn couldn't change their length as easily, meaning they only had the notes in their overtone series to work with--major chords built upon the fundamental, mostly. In order to play more than a note or two in any other key, the music had to either be written REALLY high--where the notes of the overtone series get closer together--or a horn of a different length was needed. So horn and trumpet players would need several horns to play in any piece that changed to keys that were not closely related.
Now in order to make things the music easier to read, the tradition was that the fundamental pitch of each horn (F on the F horn, Bb on the Bb horn, etc) would be notated in music as a C. This made it so that the player could easily just pick up a longer or shorter horn, and the written music would look the same, and the physical sensation of playing the horn--such as distance between overtone notes--would be the same (or nearly so), but notes of the correct key would be coming out of the bell.
As instrument design progressed, horns and trumpets came with extra tuning slides of various lengths, so that a whole new horn was not needed to play in other keys, but rather you could take a short tuning slide out and put a longer one in, putting the horn in a different key. These slides were called crooks because by the time of Weber and Wagner, composers were changing keys so quickly and fluently, that the slides had to be shaped with a crook in them to hang over the arm of the performer to facilitate quicker slide changes.
With the invention of the valve in 1815, and its subsequent adoption/popularization, this practice fell out of favor (much to Brahms' chagrin: he loved the sound of the natural horn, and hated the valve horn). So the tuba doesn't have this tradition of transposition, but rather it reads the notes on the page as they are, and the player will play that note based upon the pitch of their instrument. The trumpet and horn, though kept the tradition of transposition even after the invention of the valve. The Bb trumpet became standard. Modern players play a lot on both Bb and C trumpets and need to be able to read many different transpositions on both instruments. The horns have kinda settled on the F horn, but need to be able to read in any transposition.
However, one caveat must be included here. When the valve came to be, inventors like Adolph Sax, created whole families of instruments that were meant to sound the same over the entire range of music. The saxophone family alternates Bb and Eb instruments (Bb for soprano, Eb for Alto, Bb for Tenor, Eb for Baritone, Bb for Bass, etc). This made it so that a player of one instrument could pick up another instrument and play the same fingerings for the same written music and be okay. The third space C is fingered the same on all the saxophones, and depending on which saxophone it is, you'll get either a Bb or an Eb coming out of the instrument.
Sax also invented the saxhorn, which accounts for euphoniums, alto horns, and some tubas, also alternating (Eb for alto/tenor horns, Bb for baritone/euphonium, Eb for bass tuba, BBb for contrabass tuba, etc). This is particularly useful in the British Brass Band world, where everyone (except the bass trombone for some reason) reads treble clef parts in Bb or in Eb. Again, the idea here is that a euphonium player can move to tenor horn and read the music the same way with the same fingerings and be in the right key without having to think about the key of the piece AND the key of the horn AND the fingerings that go with both. | [
"Many transposing instruments are pitched in B-flat major, including the clarinet, trumpet, tenor saxophone, and soprano saxophone. As a result, B-flat major is one of the most popular keys for concert band compositions.\n",
"The sopranino saxophone and E♭ clarinet sound in the concert pitch ( C ) a minor third h... |
Is Civil War revisionist history going on? | Oh man, the US Civil War has seen revisionism since before it was over. | [
"In the aftermath of the Civil War and Reconstruction, new battles took place over the construction of memory and the meaning of historical events. The earliest historians to study Reconstruction and the Radical Republican participation in it were members of the Dunning School, led by William Archibald Dunning and ... |
Is there an effect the moon has on the atmosphere similar to the effect it has on the ocean by creating the tides? | These comments are a bit misleading. The atmospheric tide caused by the sun is overwhelmingly due to thermal tides, much unlike the gravitational tides caused by the moon and to a lesser extent, the sun. The moon's (and the sun's) gravity has little to do with atmospheric tides. | [
"The theoretical amplitude of oceanic tides caused by the Moon is about at the highest point, which corresponds to the amplitude that would be reached if the ocean possessed a uniform depth, there were no landmasses, and the Earth were rotating in step with the Moon's orbit. The Sun similarly causes tides, of which... |
if hypothetically every u.s. state successfully seceded into a sovereign state, would the federal government reign over the last remaining state? how would this work? | This scenario would never happen, the federal government wouldn't allow it.
But I'll play it out. No, the federal government would dissolve. If the states decided to break apart the federal government would fall apart because it exists as a unified front for the states. | [
"The clause has served this same function since then whenever a proposal to partition an existing state or states has come before Congress. New breakaway states are permitted to join the Union, but only with the proper consents. Of the 37 states admitted to the Union by Congress, three were set off from an already ... |
How did Greece didn't see the impending threat of Roman empire and do something to stop it ? | First off, there was no such thing as "Greece" whilst the Roman Republic was on the rise.
There was a multitude of indepenent Greek city states, such as Athens, Corinth or Sparta. Sometimes, these would align in leagues like the Achaean or Aetolian leagues, to defend themselves against some kind of threat or threaten some kind of common enemy. (Often, another league.) There was Macedon, the homeland of Philip III and Alexander the Great, which had more or less asserted itself as Greece's overlord when those two ruled, but now was just one of many Hellenistic successor states to the great empire of Alexander. It frequently tried to re-assert its dominance over various cities or parts of the Greek peninsula, leading to many a war. There was also Epirus, an up-and-coming kingdom on the eastern coast of Adriatic, which though it had never been a part of Alexander's domain, firmly stood in the influence of Greek and Hellenistic thought and culture. Finally, we must not forget the Greek diaspora: many a Greek colony had been founded even before Alexander started conquering, on the coasts of the Black Sea, Sicily, southern Italy and even as far afield as France (Massilia) and Spain. (Emporion.)
Southern Italy is particularly relevant to your question: it was so thoroughly dominated by Greek colonies that it was called *Megálē Hellás* or *Magna Graecia*: Great(er) Greece. It was this part of the Greek world that first came into contact with the Romans.
Now, as should be clear, none of these parts and entities I named were united. They were forever fighting one another, or the other Successor Kingdoms, or the Carthaginians, or various local peoples. Alliances and leagues were made and broken with dizzying frequency, and nobody was able to assert himself as the undisputed master of the Greek world as Alexander had been. (And even then, he had not ruled over all Greeks.)
So who was going to stop the Romans? Not the southern Greek city states, who were far more worried about their neighbours or the Antigonid Macedonians. Not those of Sicily, for they were preoccupied with Carthage. Not the Macedonians themselves, for they were struggling to hold on to their dominions and at times to even survive against Epirus to their west. Let alone the Ptolemies or Seleucids all the way in the east.
Finally, the Greeks in *Magna Graecia* did try to stop the Romans, shortly after they had defeated the Samnites. This was very early on in the history of the Roman empire, you should note. There hardly was an empire to speak of. Rome was a regional Italic power, very successful in conquering and integrating their neighbours, but definitely not something that looked like it could threaten the Greek world as a whole.
Despite this, the city of Tarās(Tarentum) asked and got the help of Pyrrhus of Epirus, one of the best generals of his day and commander of one of the finest professional armies in the Hellenistic tradition. All that was "more technologically advanced and had a better knowledge of war" was represented in Pyrrhus' army.
And he lost the war.
Pyrrhus beat the Romans twice, but it's those battles that give us the term "Phyrric Victory." He also got entangled with the Carthaginians in Sicily, and the third battle against the Romans at Beneventum, though still not tactically decisive, proved too much. He withdrew to Greece. Rome was left to rule Italy. Despite all his apparent advantages, Greek military sophistication had proven unable to decisively defeat Rome.
There would be further attempts at intervention. During the second Punic War, when Hannibal was marching up and down Italy, Carthage and Macedon tried to ally against Rome, so as to negate the potential threat. But other Greek cities of the Aetolian League saw Macedon as the greater threat to their survival, and allied with Rome. They occupied the Macedonians until the Romans could win their war against Carthage. Later, when Rome could focus its full attention east, two further Macedonian wars followed and saw the (at this time highly experienced, thanks to decades of war against the Carthaginians) Roman armies again victorious against their Greek counterparts.
Whilst this was going on, the Seleucid empire under Antiochus the Great tried to intervene also. He send armies west to Greece, but the Romans again proved too strong, and his empire was facing many other troubles in the east. Also, the Romans still had other Greeks on their side in all these conflicts. There's a reason that "divida et impera" is a Latin phrase.
By the time Pompey the Great was marching up and down the Eastern Mediterranean, making and unmaking kings and incorporating provinces left and right, it was far too late for anyone to do anything about Rome's rise.
In summary: "Greece" was never united, and never able to truly make a common cause against Rome. Nonetheless, many of the most powerful Greek kings and kingdoms of their day did try to smack down Rome before they became too powerful. All lost.
As Philip Sabin puts it in his *lost battles:*
> Lendon has highlighted very well how Greek authors such as Polybius tended to ascribe military success to better tactics, techniques or equipment, whereas Roman writers like Caesar or Livy were more concerned with the superior bravery and *virtus* of the victorious soldiers. The evidence of both Greek and Roman battles lends much more support to the Roman interpretation.
(The Lendon he refers to here is: Lendon, E.*Soldiers & Ghosts: a History of Battle in Classical Antiquity.* New Haven: Yale University Press (1999) )
In other words: being technologically advanced and having a better knowledge of war doesn't seem to really have helped the Greeks. Roman diplomacy, the quality of Roman armies (at a particular high during this time, thanks to the Punic wars, according to Goldsworthy.) and the reserves of manpower Rome had due to their militia system and many allies proved far more decisive. | [
"The reasons for Rome's intervention in Greece from the 3rd century BC are many: a call for help from the cities of Illyria; the fight against Philip V of Macedon, whose naval policy troubled Rome and who had been an ally of Hannibal’s; or assistance to Macedon’s adversaries in the region (Pergamon, Rhodes and the ... |
has obama done a good job as potus? | Reddit is a terrible place to find this out.
As for my opinion (which is all you'll get here, with biased sources), Obama is the 5th-best president in our country's history. All the good he has done must be accompanied with the reminder that he has faced the most blatant and extreme obstructionism in the history of the office. | [
"He has also been referenced by the media as an expert concerning Barack Obama's political strategies as related to unemployment ratings and economic policy. Darity criticized Obama's October 2011 economic strategy as \"bribing the private sector to put people back to work. I was hoping that there would be some eff... |
Why did the Great War last so long? Why did people in the West keep fighting? | Why has any democracy carried on with a war that was going only so-so? Look at the Vietnam war, I think it took 6+ years of fighting before a simple majority of the country thought the US should get out.
To answer your question in a word, pride. Humans don't do a good job admitting that we might be wrong. Especially when our brother or father or husband might have died at the front. Do we really want to accept that they died just to restore "status quo ante bellum?"
Plus I don't think there was ever a point in which there wouldn't be a "losing" side in the negotiations. Even if there had been successful negotiations in 1916 or 1917, Germany still would have likely been forced to give up some colonies. Now as a German citizen who's lost loved ones, that's a tough proposition to swallow.
People hate compromising and surrendering, no matter how rational it might be. War is like gambling, much to gain, much to be lost, and if you're not careful you'll bankrupt yourself and everyone around you trying to win. | [
"The experiences of the war in the west are commonly assumed to have led to a sort of collective national trauma afterward for all of the participating countries. The optimism of 1900 was entirely gone and those who fought became what is known as \"the Lost Generation\" because they never fully recovered from their... |
why is there still a slight delay on my tv even when i have game mode turned on? compared to crt tv's seeming to be instant? | Why was this downvoted? | [
"All first-party cartridges and most third-party software titles feature a 12-second pause before presenting the game select screen. This delay results from an intentional loop in the console's BIOS to enable on-screen display of the ColecoVision brand. Companies like Parker Brothers, Activision, and Micro Fun bypa... |
Fictional historical people | Prester John. 500 years of European stories about a Christian monarch in India, or Central Asia, or Ethiopia. The Wikipedia entry is pretty good: _URL_0_
(I've been fascinated by that guy since I first heard of him, but can't claim any expertise about him.) | [
"The prototypes of real historical figures operate in the story. The main figure, Wanderer - is one of the most mysterious personalities during the last years of the Russian Empire – Grigori Rasputin. The faithful fan of the Wanderer \"Fanny Zarubina\" (who is derisively called \"The Cow\") is Anna Vyrubova, the la... |
what would happen if you pulled your keys out of the ignition while driving? | 70s and 80s GM cars had a weak retention pin, I remember it was always funny to reach over and rip the keys out of your friend's ignition while they were driving to see their reaction. Stupid, but funny. | [
"When the key is turned in the ignition cylinder, the car's computer transmits a radio signal to the transponder circuit. The circuit has no battery; it is energized by the radio signal itself. The circuit typically has a computer chip that is programmed to respond by sending a coded signal back to the car's comput... |
how do machines generate cold air | Air conditioning and refrigerators use a property of gas known as Gay-Lussac's Law. This basically states that as you increase pressure on a gas, the temperature increases. Conversely, as you decrease pressure of a gas, it absorbs energy and becomes cooler.
So AC and refrigerators work by compressing a coolant. This compression generates heat that is dispersed by by a fan that runs outside air over the compressor. The coolant is compressed so that it actually becomes a liquid. The liquid coolant is then pumped inside the area that is to be cooled. The coolant is then allowed to become gas again in an evaporator coil. As the liquid becomes gas, it absorbs heat (becoming cooler). Another fan passes air over the coil and the heat absorbed by the change in state of the coolant cools down the air. It's this cool air that is circulated in the fridge or inside of the house. From the evaporator coil, the coolant is then pumped back outside to the compressor to continue the cycle.
From a thermodynamic standpoint, heat is generated by compressing the coolant outside and the same amount of heat is absorbed from the air being blown over the evaporator coil inside. This results in cooler air inside the dwelling or refrigerator. | [
"Air-cooled and evaporative cooled chillers are intended for outdoor installation and operation. Air-cooled machines are directly cooled by ambient air being mechanically circulated directly through the machine's condenser coil to expel heat to the atmosphere. Evaporative cooled machines are similar, except they im... |
Are there any creatures that use endothermic reactions for defense? | Lots of things are exothermic. Combustion, for instance. Very few biological reactions are strongly endothermic enough to be useful as a defense mechanism.
"Get back or I'll freeze you to death!" | [
"Kolbert points out that there is an evolutionary arms race, in which each species must be equipped to defend against their potential predators, and need to be more fit than their competition. A species has no defense if it encounters a new fungus, virus, or bacterium. This can be extremely deadly, as it was in the... |
Does the 'space' inside a black hole move faster than the speed of light? | *EDIT: Multiple edits in many places. Apologies for that.*
I wish people would stop thinking in terms of speed when it comes to black holes. It's a very confusing way to describe it. Seems simple at first, but it leads you into error later.
A much more useful way to think of a BH is via topology. When inside the event horizon, no matter which way you're looking at, you're looking at the center. Spacetime itself is so twisted, knotted into itself, that all trajectories inside the event horizon, no matter how you draw them, eventually end in the center. There is no way up - worse, *there is no up*. There is only down, and down, and down.
> does it mean that the space through which the light is traveling, actually moves faster than the speed of light?
Space is not something that can "move". Putting these two notions together makes no sense.
You're thinking as if you're swimming upriver, but you're overwhelmed by the speed of water. It's not like that. Space is not water.
> I 'know' that nothing is faster than the speed of light - that is the maximum speed.
It's not as simple as that. Most people think of the speed of light as some sort of cosmic police that doesn't let you go faster than c. But that's not how it works.
Reality is, as you get closer and closer to c, the relations of space and time become "distorted". Time appears to stretch out, and space appears to be compressed. The closer you get to c, the stronger the distortion. The reason why you can't reach c is that, if you did, time would stretch out to infinity, space would compress down to nothing, and all sorts of divisions by zero would come out of the math. Space and time would be like nothing you could ever imagine. Math (the equations of motion) would be "broken".
Further, speed of light is a "limit", an obstacle for space exploration, only for the bystanders back on Earth. But the rocket traveling at relativistic speeds has a different experience:
For you, sitting here on Earth, it seems like my rocket travels at "only" 0.9999999...c towards the Andromeda Galaxy, and would reach it in 2.5 million years.
But for me, inside the rocket, because of space-time relativistic distortion, the journey to Andromeda could be very short indeed; maybe a few decades, or years, or days, or even a few seconds. It all depends on how fast I accelerate.
It appears to be a very long journey from where you're sitting, but it's pretty short (time-wise) for me - *and we are both correct!*
So be careful when thinking of c as a "limit"; it's a complex and subtle issue. True, you can never measure speed higher than c, no matter what you do - that's one of the few things that are absolute in this Universe. But you can travel as far as you want, in as short a time as you want; relativity itself allows you to do that. | [
"As a black hole rotates, it twists spacetime in the direction of the rotation at a speed that decreases with distance from the event horizon. This process is known as the Lense–Thirring effect or frame-dragging. Because of this dragging effect, an object within the ergosphere cannot appear stationary with respect ... |
Did the Ottoman Caliph actually hold power over the Muslim ummah, or was it just a ceremonious title? | I'll try to answer your question, sorry if it doesn't satisfy you
It was mostly the latter. First of all. generally speaking (with exceptions, like in the Muslim kingdoms/communities in the Indian Ocean), the classical concept of a single caliph for the whole Islamic community had had no force since the 13th century with the destruction of Abbasid Baghdad in 1258. There were, to be sure, self-aggrandizing rulers from various parts of the Muslim world including who sometimes included "caliph" among their list of titles. Yet when they did so, it was in a manner virtually interchangeable with "sultan", lacking any implication of descent from earlier caliphs or an exclusive claim to the title or to universal authority. This general disregard for the past prestige of the caliphate seems to have been shared by intellectuals as well as politicians. In the centuries after the fall of Baghdad, Muslim scholars from the extreme traditionalist Ibn Taymiyya to the hyper-rationalist Ibn Khaldun, seem to have reached a basic consensus that the caliphate as an institution no longer had relevance for the times in which they lived.
It was still quite the case when the Ottomans came along. In the first place, There is no evidence to suggest that Selim aspired to the office of caliph before his conquest of Egypt, remaining silent about both in all of his pre-conquest correspondence with the Mamluks. Nor did he make a visible effort to claim these offices immediately following his conquest, failing to make any systematic mention of them in the various *fethnāmes* sent to announce his victory to officials and dignitaries of his realm, to vassals and foreign rulers, and to his heir, the future Sultan Suleiman. Instead, the title was acclaimed to him by people living entirely outside the territories under his control. The first public acknowledgement of Selim as *Khadim al-Haramayn* (Custodian of the Holy Mosque, an equally prestigious title) would come four years later from the Sharif of Mecca. Immediately following Selim’s conquest of Egypt, while he was still in Cairo, the Sharif sent an official delegation headed by his own son to meet the sultan and, in a gesture heavy with political significance, to hand over to him the keys to Mecca. It was only after this public act that Selim, in a letter to the ruler of Shirvan, seems to have for the first time referred to the "*khilāfet-i ālīye"* (exalted caliphate) and to the insertion of his own name in the *hutbe* of Mecca, reasoning that the failure of the Mamluks to protect the hajj routes had made it incumbent on him to assume this role. Then, in the following year, it was an Indian Ocean Muslim, Malik Ayaz of Gujarat, who as the governor of Diu became the first foreign ruler to spontaneously acknowledge Selim as “Caliph of the Faith” in a letter congratulating him on his victory
Despite its mostly ceremonial title however, The Ottomans did sometimes use it in a politicized manner to mobilize or to correspond with Muslim communities outside the empire. One such example is in the 16th century, when the Ottoman Empire influenced and interacted with Muslim Powers in the Indian Ocean to fight the Portuguese, which i will briefly describe
The treaty of Tordesillas led to King Manuel I of Portugal claiming a new imperial title: "Lord of the Conquest, Navigation and Commerce of Ethiopia, Arabia, Persia and India", as he hoped to be recognized as these rulers’ superior, a "king of kings" or universal emperor, whose authority transcended the physical possession of any specific territory. Because Portuguese ambitions were concerned first and foremost with the transit spice trade, and since trade routes to and from the Red Sea were trafficked principally by Muslim merchants, Portuguese claims would be measured in its ability to prevent Indian Ocean Muslims from travelling to the Red Sea for trade and *hajj*. For the first time in history a non-Muslim power emerged in the Indian Ocean that was not only capable of preventing disparate Muslim communities from maintaining contact with one another by means of *hajj* but was actually compelled to do so according to the terms of its own claims to universal sovereignty. The Portuguese then started to raid and blockade parts of the Red Sea, and as a result of this sustained and organized violence, the Muslim Indian Ocean communities was primed for a radical re-politicization of the ideal of the Muslim *Umma.* With this in mind, the spontaneous acclamation of Selim as both "Caliph" and "Servant of the Two Holy Cities" was a potential two-edged sword. On the one hand, the notion that the Ottoman sultan was now responsible for protecting Muslim merchants and pilgrims throughout the Indian Ocean (and presumably, elsewhere too) implied that his legitimacy could be called into question by events far outside of the empire’s borders, beyond his control, and possibly even unknown to him if he failed to fulfill these obligation. On the other hand, if the sultan were able guarantee the safety of the Indian Ocean hajj, or at least make a credible effort to do so, he might expect a measure of allegiance in return from Muslims throughout maritime Asia, regardless of whether or not they were actually Ottoman subjects. The Ottomans had been nurturing the title caliph since the early reign of Süleyman. These efforts were directly connected with the consolidation of Ottoman rule in Egypt and were spearheaded by the grand vizier Ibrahim Pasha, Süleyman’s closest confidant and a leading proponent of Ottoman military engagement in the Indian Ocean. In 1538, a fleet of over seventy ships eventually did set sail to India from Suez, beginning the history of direct Ottoman military involvement in maritime Asia. With the departure of this fleet, a full-blown revival of the concept of the Universal Caliphate in a thoroughly Ottoman guise began to take shape in the following decades. The clearest evidence for this dates from the 1560s and emerges from a series of diplomatic exchanges between the Ottomans and the Sultan of Aceh, Ali Ala’ad-Din Ri’ayat Syah. In the first letter of this exchange, sent from Aceh in 1564 and addressed to Suleiman the Magnificent, the Ottoman sultan is repeatedly addressed as "caliph" by Ali Ala’ad-Din Ri’ayat Syah and is assured that in this capacity his name is read in the *hutbe* in all the mosques of Aceh. Moreover, the letter indicates that Suleiman is being similarly named in the *hutbes* of Sri Lanka, Calicut, and the Maldives, all places strategically located along the maritime trunk routes to the Red Sea, and these communities’ recognition of the sultan as defender of the universal *Umma* was now expressed in direct expectation of weapons, ships, and technical expertise in return, in order to continue the ongoing fight against the Portuguese
**Sources:**
*Tordesillas and the Ottoman Caliphate: Early Modern Frontiers and the Renaissance of an Ancient Islamic Institution* and *The Ottoman Age of Exploration* by Giancarlo Casale
*Legitimizing The Order: The Ottoman Rhetoric of State Power* by Hakan T. Karateke and Maurus Reinkowski | [
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